Except as
permitted by Sections 107 and 108 of the 1976 United States Copyright Act, no
part of this publication may be reproduced or distributed in any form, or by
any means, or stored in any database or retrieval system, without the prior
written permission of the copyright owner.

Information
contained in this work has been obtained by Mainstream Engineering Corporation
from sources believed to be reliable. However, neither Mainstream Engineering
Corporation nor its author guarantees the accuracy or completeness of any
information published herein, and neither Mainstream Engineering Corporation
nor its author shall be responsible for any errors, omissions, or damages
arising out of the use of this information. This work is published with the
understanding that Mainstream Engineering Corporation and its author are
supplying information but are not attempting to render engineering or other
professional or technical services. If such services are required, the
assistance of an appropriate professional should be sought.

The information in this course is
intended for educational purposes only. Procedures described are for use only
by qualified air conditioning and refrigeration service technicians. This
training course is not a substitute for any Manufacturer's Operating Manual.

Take safety precautions when using
all equipment. Improper use of equipment can cause explosion and serious personal
injury. Always read the entire Manufacturer's Operator Manual before turning on
any equipment for the first time. Use extreme caution when working with molds,
spores and other airborne or surface contaminants, since inhalation of these
air contaminants can cause serious medical problems, including death. Do not
use any protective equipment if you do not understand its operation and it is
not in perfect working order. Where procedures described in this manual
differ from those of a specific equipment manufacturer, the equipment
manufacturer's instructions should be followed. Again, misuse of safety or
protective equipment can cause personal injury.

Technical and legislative
information presented in this book is current as of the date of publication. Due
to rapidly advancing technology and changing regulations, no representation can
be made for the future accuracy of the information. Visit the EPA's Indoor Air
Quality Building Page at http://www.epa.gov/iaq/ for the latest details.

The manual was intended to serve
as a training manual to help technicians successfully pass Mainstream’s Indoor
Air Quality Technician (IAQ Tech) certification examination. This training
manual is the first step in the learning process; technicians are urged to
obtain additional information from the local health department, product
manufacturers, the EPA website and ASHRAE. The manual is not intended to teach
building remediation or air conditioning/refrigeration system installation,
troubleshooting, or repair. Experienced service technicians will notice that a
lot of information is not new on the topic of indoor air quality; most of the
procedures for maintaining clean and dry building envelopes have been in use
for years. However, with today's tighter building envelopes, these skills must
now be applied more diligently than ever.

Users of this manual should also
be aware of available information that is not included here. The intent is to
present a basic introductory course concentrating on practical, basic
information that is most needed and can be readily applied on the job with the
most effective results. The reader is encouraged to seek additional information
from OSHA, EPA and other parties referenced at the end of this manual. This
manual should be the first step in a continual training program. Please visit
our website at www.qwik.com for the latest
information and products.

This manual is in a continual
state of evolution and revision, partly because of the changing EPA regulations
and partly because of the information feedback from technicians in the field. If
there are sections of this manual that require improvement, or there are
missing areas that you believe to be important, please write us a short note and
we will see that the improvements are incorporated into future editions. In the
past, we have received very useful comments and suggestions from HVAC/R
technicians in the field, and to all those who have helped in the past, we owe
a sincere debt of gratitude. Suggestions on the improvement of this course or
any Mainstream product will always be welcomed. To submit suggestions, comments
or complaints, please write to Robert P. Scaringe, Ph.D., P.E., IAQ Tech
Certification Program, Mainstream Engineering Corporation, Pines Industrial
Center, 200 Yellow Place, Rockledge, Florida 32955.

Mainstream Engineering Corporation
assumes no liability for the use of information presented in this publication. This
information is presented for educational purposes only. Manufacturer's Operator
Manuals must be consulted for the proper operation of any piece of equipment. This
manual is not intended to teach fundamental air conditioning or refrigeration
system techniques or safety practices. Likewise, this manual is not intended to
teach safe mold remediation practices or mold handling techniques. Rather, the
purpose of this manual is to point out the significant issues involved with
working with these substances and how the HVAC system can affect indoor air
quality. This manual assumes the technician possesses both EPA-Approved Section
608 certification and PM Tech certification. If you do not yet hold these certifications, pleasevisit our website atwww.qwik.com to obtain this training first.

In the last several years, a growing body of scientific
evidence has indicated that the air within buildings can be more seriously
polluted than the outdoor air. It is also clear that HVAC systems are the
primary mechanism to condition and clean the air in buildings and commercial
buildings. Likewise, problems in the HVAC system are also the primary factor in
resulting problems associated with indoor air quality. In a
properly constructed building, it is the HVAC system that can most
significantly affect the quality and cleanliness of the indoor air. Therefore,
the HVAC technician is the ideal individual to implement Indoor Air Quality
improvements in a structure. Clearly, the HVAC Technician, after being trained
in IAQ matters, is the individual best suited to service, adjust, inspect, and
clean the HVAC's network of ducting, heat exchangers, condensate pans,
humidifiers and blowers. With this in mind, this training program was
developed.

This Training and Certification program is designed to help
advance the fundamental principles necessary to improve the quality of
conditioned air inside buildings. Certification is available on-line at www.qwik.com
.

The IAQ Tech certification exams consist of
25 questions. Technicians can take the IAQ Tech certification exam as many
times as necessary (passing grade is 21 correct out of the 25 questions or
84%). The exams are open-book and technicians have a maximum of three hours to
complete each exam. If you retake the exam, you will automatically be given a
different set of questions from the test bank.

IAQ Tech certification is needed to offer the
full warranty benefits of Mainstream's QwikProducts™ to your
customers. Three types of certification are available: Apprentice, Journeyman,
and Master IAQ Tech. Prior to obtaining any of Mainstream's IAQ
certifications, the technician must have an EPA 608 certification from an
EPA-approved certifying agency, such as Mainstream.

The IAQ Tech certification exam is available on-line. You
can take the exam online when you are ready. The exam questions are related to
Indoor Air Quality and the proper use of QwikProducts™ and
the Air Conditioning system to improve indoor air quality and prevent mold
formation.

Mainstream reserves the right to revoke the IAQ Tech
certification given to any individual, at any time, and without prior notice,
for excessive customer complaints, unethical or illegal service practices,
failure to meet Mainstream's professional requirements, or any other reason
deemed justifiable by Mainstream employees. Mainstream is under no legal
obligation to disclose the reason for the revocation.

Levels of IAQ Tech Certification

Apprentice IAQ Tech

a) EPA Section 608 certification from Mainstream or any
other EPA-approved testing organization,

b) successfully completing the IAQ Tech exam with a score of
84% or better.

Documentation to prove EPA certification may be necessary if
Mainstream does not already have this documentation. If you pass your exam and
the exam status reads "PASSED", you must provide Mainstream with
proof of 608 certification.

Journeyman IAQ Tech

This certification includes all the requirements of the
Apprentice IAQ Tech (above) plus at least five years verifiable experience in
the HVAC/R trades. Documentation to substantiate this experience is required. However,
if you hold a Journeyman PM Tech certification you will automatically be issued
a Journeyman IAQ certification as well.

Master IAQ Tech

This certification includes all the requirements of the
Apprentice IAQ Tech plus at least 10 years verifiable experience in the HVAC/R
trades. Documentation to substantiate this experience is required. However, if
you hold a Master PM Tech certification you will automatically be issued a
Master IAQ certification as well.

Substance (such as dust mites,
mold or mold spores that can cause an allergic reaction

APR

Air purifying respirator

ASTM

American Society for Testing and
Materials

Biocide

Substance or chemical that kills
organisms such as molds

Building Occupants

Describes people who spend
extended time periods in the building. Clients and visitors are also
occupants; they may have different tolerances and expectations from those who
spend their entire workdays in the building, and are likely to be more
sensitive to odors.

Building RelatedIllness
(BRI)

Refers to illness brought on by
exposure to the building air, where symptoms of diagnosable illnesses are
identified (e.g., certain allergies or infections) and can be directly attributed
to environmental agents in the air. Legionnaire's disease and
hypersensitivity pneumonitis are examples of BRI that can have serious, even
life-threatening consequences.

Dew Point

If the air is gradually cooled
while maintaining the moisture content constant, the relative humidity will
rise until it reaches 100%. This temperature, at which the moisture content
in the air will saturate the air, is called the dew point. If the air is
cooled further, some of the moisture will condense.

Dry-build Temperature

The temperature of the air
measured with a dry thermocouple or thermometer with a dry bulb. The Dry-Bulb
and Wet-Bulb temperatures can be used together to determine relative
humidity.

EPA

Environmental Protection Agency

Fungi

Fungi are neither animals nor
plants and are classified in a kingdom of their own. Fungi include molds,
yeasts, mushrooms, and puffballs. In this document, the terms fungi and mold
are used interchangeably. Molds reproduce by making spores. Mold spores waft
through the indoor and outdoor air continually. When mold spores land on a
damp spot indoors, they may begin growing and digesting whatever they are
growing on. Molds can grow on virtually any organic substance, providing
moisture and oxygen are present. It is estimated that more than 1.5 million
species of fungi exist.

Fungicide

Substance or chemical that kills
fungi

HEPA

High-Efficiency Particulate Air

Hypersensitivity

Great or excessive sensitivity

Humdity

The water vapor mixed with air
in the atmosphere

Humidity Ratio

Also known as Specific Humidity,
the pounds of water contained in a pound of dry air

IAQ

Indoor Air Quality

MERV

Minimum Efficiency Reporting
Value

Mold

Molds are a group of organisms
that belong to the kingdom Fungi. In this document, the terms fungi and mold
are used interchangeably. There are over 20,000 species of mold.

mVOC

Microbial volatile organic
compound, a chemical made by a mold that may have a moldy or musty odor

NIOSH

National Institute for
Occupational Safety and Health

NFPA

National Fire Protection
Association

OSHA

Occupational Safety and Health
Administration

PAPR

Powered air purifying respirator

PPE

Personal Protective Equipment

Relative Humidity

The ratio of weight of water in
the air relative to the maximum weight of water that can be held in saturated
air

Remediate

Fix

Sensitization

Repeated or single exposure to
an allergen that results in the exposed individual becoming hypersensitive to
the allergen

Spore

Molds reproduce by means of
spores. Spores are microscopic; they vary in shape and size (2-100
micrometers). Spores may travel in several ways-they may be passively moved
(by a breeze or water drop), mechanically disturbed (by a person or animal
passing by), or actively discharged by the mold (usually under moist
conditions or high humidity).

Stack Effect

The pressure driven flow
produced by convection (the tendency of warm air to rise)

UL

Underwriters Laboratories

Wet-bulb Temperature

The temperature of the air
measured with a wet thermocouple or thermometer with a wet bulb. The Dry-Bulb
and Wet-Bulb temperatures can be used together to determine relative
humidity.

Section
I:

Introduction

In the last several years, a growing body of scientific
evidence has indicated that the air within buildings can be more seriously
polluted than the outdoor air in even the largest and most industrialized
cities. Research indicates that people spend approximately 90 percent of their
time indoors. Thus, for many people, the risks to health may be greater due to
exposure to air pollution indoors than outdoors. In addition, people who may be
exposed to indoor air pollutants for the longest periods of time are often
those most susceptible to the effects of indoor air pollution. Such groups
include the young, the elderly, and the chronically ill, especially those
suffering from respiratory or cardiovascular disease.

Asthma afflicts about 20 million Americans, including 6.3
million children. Since 1980, the largest growth in asthma cases has
been in children under five. In 2000 there were nearly two million emergency
room visits and nearly half a million hospitalizations due to asthma, at a cost
of almost $2 billion, and causing 14 million school days missed each year.

Indoor pollution sources that release gases or particles
into the air are the primary cause of indoor air quality problems in buildings.
Inadequate ventilation can increase indoor pollutant levels by not bringing in
enough outdoor air to dilute emissions from indoor sources and by not carrying
indoor air pollutants out of the building. High temperature and humidity levels
can also increase concentrations of some pollutants.

Introduction

There are many sources of indoor air pollution in
any building. These include combustion sources such as oil, gas, kerosene,
coal, wood, and tobacco products; building materials and furnishings as diverse
as deteriorated, asbestos-containing insulation, wet or damp carpet, and
cabinetry or furniture made of certain pressed wood products; products for
cleaning and maintenance, personal care, or hobbies; central heating and
cooling systems and humidification devices; and outdoor sources such as radon,
pesticides and outdoor air pollution.

The relative importance of any single source depends on how
much of a particular pollutant is given off and how hazardous those emissions
are. In some cases, factors such as how old the source is and whether it is
properly maintained are significant. For example, an improperly adjusted gas
stove can emit significantly more carbon monoxide than one that is properly adjusted.

Some sources, such as building materials, furnishings, and
products like air fresheners, candles and scented oils release pollutants more
or less continuously. Other sources, related to activities carried out in the
building, release pollutants intermittently. These include smoking, the use of
un-vented or malfunctioning stoves, furnaces, or space heaters, the use of
solvents in cleaning and hobby activities, the use of paint strippers in
redecorating activities, and the use of cleaning products and pesticides in
housekeeping. High pollutant concentrations can remain in the air for long
periods after some of these activities.

Recent EPA studies have identified indoor air
pollution as one of the most important environmental risks to the nation's
health. With the advancement of modern technology, the number and types of
contaminants released into indoor air have increased dramatically.

The indoor environment in any building is a result of the
interaction between the site, climate, building system (original design and
later modifications in the structure and mechanical systems), construction
techniques, contaminant sources (building materials and furnishings, moisture,
processes and activities within the building and outdoor sources), and building
occupants.

Four elements are involved in the development of indoor air
quality problems:

Source: There is a source of
contamination or discomfort indoors, outdoors, or within the mechanical
systems of the building.

HVAC: The HVAC system is not able to control
existing air contaminants and ensure thermal comfort (temperature and
humidity conditions that are comfortable for most occupants).

Distribution: One or more pollutant pathways
connect the pollutant source to the occupants and a driving force exists
to move pollutants along the pathway(s).

Occupants: Building occupants are present.

It is important to understand the role that each of these
factors may play in order to prevent, investigate, and resolve indoor air quality
issues.

Indoor air contaminants can originate within the building or
be drawn in from outdoors. If contaminant sources are not controlled, IAQ
problems can arise, even if the HVAC system is properly designed and well
maintained.

It may be helpful to think of air pollutant sources as
fitting into one of the following categories. The examples given for each
category are not intended to be a complete list.

Indoor air often contains a variety of contaminants that are
far below any standards or guidelines for occupational exposure. Given our
present knowledge, it is difficult to relate complaints of specific health
effects to exposure to specific pollutant concentrations, especially since the
significant exposures may be to low levels of pollutant mixtures.

The HVAC system includes all
heating, cooling and ventilation equipment serving a building: furnaces or
boilers, chillers, cooling towers, air handling units, exhaust fans, ductwork,
filters, and steam (or heating water) piping. Most of the HVAC discussion in
this course applies to central HVAC systems.

A properly designed and functioning
HVAC system provides thermal comfort (cooling and dehumidification or heating
and humidification), and filters the air. In addition, commercial HVAC systems
also; distribute adequate amounts of outdoor air to meet ventilation needs of
all building occupants and isolate and remove odors and contaminants (through
pressure control and exhaust fans).

A number of variables interact to determine whether people
are comfortable with the temperature of indoor air. The activity level, age and
physiology of each person affect the thermal comfort requirements of that
individual.

Uniformity of temperature is important to comfort. When the
heating and cooling needs of rooms within a single zone change at different
rates, rooms that are served by a single thermostat may be at different
temperatures. Temperature stratification is a common problem caused by
convection, the tendency of light and warm air to rise, and heavier and cooler
air to sink. If the air is not properly mixed by the ventilation system, the
temperature near the ceiling can be several degrees warmer than at floor level.
Even if the air is properly mixed, un-insulated floors over unconditioned
spaces can create moisture problems, and discomfort in some climate zones.
Large fluctuations of indoor temperature can also occur when controls have a
wide dead band (a temperature range within which neither heating nor cooling
takes place). Adjusting the thermostats dead band or replacing the thermostat
with a new thermostat that uses a narrower dead band or an improved
anticipating control algorithm, such as a PID controller, can easily remedy
some of these problems. The installation of a dehumidifier to a central AC
system can provide reduced humidity.

Radiant heat transfer may cause people located near very hot
or very cold surfaces to be uncomfortable even though the thermostat setting
and the measured air temperature are within the comfort range. Buildings with
large window areas sometimes have acute problems of discomfort due to radiant
heat gains and losses. The locations where complaints are usually made can
shift during the day as the sun angle changes. Large vertical surfaces can also
produce significant natural convection flows resulting in complaints of drafts.
Adding insulation to walls helps to moderate the temperature of interior wall
surfaces. Closing curtains reduces heating from direct sunlight and isolates
building occupants from exposure to window surfaces (which, lacking insulation,
are likely to be much hotter or colder than the walls).

Humidity is a factor in thermal comfort. Raising relative
humidity reduces the ability to lose heat through perspiration and evaporation,
so that the effect is similar to raising the temperature. Humidity extremes can
also create other IAQ problems. Excessively high or low relative humidity can
produce discomfort, while high relative humidity can promote the growth of mold
and mildew. To prevent mold and mildew the relative humidity must be
less than 55% in all areas of the building.

Airflow patterns in buildings
result from the combined action of mechanical ventilation systems, human
activity, and natural forces. Pressure differentials created by these forces
move airborne contaminants from areas of relatively higher pressure to areas of
relatively lower pressure through any available opening.

The HVAC system is generally the
predominant pathway and driving force for air movement in buildings. However,
all of a building's components (walls, ceilings, floors, penetrations, HVAC
equipment and occupants) interact to affect the distribution of contaminants.
For example, as air moves from supply registers or diffusers to return air
grilles, it is diverted or obstructed by partitions, walls and furnishings, and
redirected by openings that provide pathways for air movement. The movement of
people throughout the building also has a major impact on the movement of
pollutants. Some of the pathways change as doors and windows open and close. It
is useful to think of the entire building--the rooms and the connections (e.g.,
chases, corridors, stairways, elevator shafts) between them--as part of the
air-distribution system.

Natural forces exert an important
influence on air movement between zones and between the building's interior and
exterior.Both the stack effect and the wind can overpower a
building's mechanical system and disrupt air circulation and ventilation,
especially if the building envelope is leaky.

Stack effect is the
pressure-driven flow produced by natural convection (the tendency of warm air
to rise). The stack effect exists whenever there is an indoor-outdoor
temperature difference and becomes stronger as the temperature difference
increases. As heated air escapes from upper levels of the building, indoor air
moves from lower to upper floors, and replacement outdoor air is drawn into
openings at the lower levels of buildings. The resulting airflow can transport
contaminants between floors by way of stairwells, elevator shafts, utility
chases, or other openings. Stack effects can be so strong as to prevent ground
floor doors from closing; instead they are blown inward by the replacement air
rushing into the building.

Wind effects are transient and
create local areas of high pressure (on the windward side) and low pressure (on
the leeward side) of buildings. Depending on the leakage openings in the
building exterior, wind can affect the pressure relationships within and
between rooms.

The basic principle of air
movement from areas of higher pressure to areas of relatively lower pressure
can produce many patterns of contaminant distribution. Air moves from areas of
higher pressure to areas of lower pressure through any available openings. A
small crack or hole can admit significant amounts of air if the pressure
differentials are high enough (which may be very difficult to assess).

Even when the whole building is
maintained under positive pressure, there is always some location (for example,
the outdoor air intake) that is under negative pressure relative to the
outdoors. Entry of contaminants may be intermittent, occurring only when the
wind blows from a particular direction. The interaction between pollutant
pathways and intermittent or variable driving forces can lead to a single
source causing IAQ complaints in areas of the building that are distant from
each other and from the source.

If too little outdoor air enters a structure, pollutants can
accumulate to levels that can pose health and comfort problems. Unless they are
built with special mechanical means of ventilation, buildings are designed and
constructed to minimize the amount of outdoor air that can "leak"
into and out of the building. The tighter the building, the higher the
pollutant levels, when compared to buildings with more outdoor air leakage.

Outdoor air enters and leaves a building through
infiltration, natural ventilation and mechanical ventilation. In the process
known as infiltration, outdoor air flows into the building through openings,
joints and cracks in walls, floors and ceilings, and around windows and doors.
In natural ventilation, air moves through opened windows and doors. Air
movement associated with infiltration and natural ventilation is caused by
indoor and outdoor air temperature differences and by wind. Finally, there are
a number of mechanical ventilation devices, from outdoor-vented fans that
intermittently remove air from a single room, such as bathrooms and kitchen, to
air handling systems that use fans and duct work to continuously remove indoor
air and distribute filtered and conditioned outdoor air to strategic points
throughout the building. The rate at which outdoor air replaces
indoor air is described as the air exchange rate. When there is
little infiltration, natural ventilation, or mechanical ventilation, the air
exchange rate is low and pollutant levels can increase.

While commercial air ducts are fabricated from sheet metal,
most modern residential air duct systems are constructed of fiberglass duct
board or sheet metal ducts that are lined on the inside with fiberglass duct
liner. Since the early 1970s, a significant increase in the use of flexible
duct has occurred. Flexible duct is generally lined internally with plastic or
some other type of material. Internal insulation provides better acoustical
(noise) control. Flexible duct is very low cost. These products are engineered
specifically for use in ducts or as ducts themselves, and are tested in
accordance with standards established by Underwriters Laboratories (UL), the
American Society for Testing and Materials (ASTM), and the National Fire
Protection Association (NFPA).

Many insulated duct systems have operated for years without
supporting significant mold growth. Keeping them reasonably clean and dry is
generally adequate. However, there is substantial debate about whether porous
insulation materials (e.g., fiberglass) are more prone to microbial
contamination than bare sheet metal ducts. If enough dirt and moisture are permitted
to enter the duct system, there may be no significant difference in the rate or
extent of microbial growth in internally lined or bare sheet metal ducts. However,
treatment of mold contamination on bare sheet metal is much easier.Once
fiberglass duct liner is contaminated with mold, cleaning is not sufficient to
prevent re-growth and there are no EPA-registered biocides for the cleaning
of porous duct materials. We agree with the EPA, that in this
situation the replacement of the wet or moldy fiberglass duct material is
required.

Clearly, all experts agree that moisture should not be
present in ducts and if moisture is present, the potential exists for
biological contaminants to grow and distribute throughout the building. Controlling
moisture is the only effective way to prevent biological growth on any type of
air ducts.

Strategies to
Prevent Biological Growth in HVAC Systems

▶Correct
any water leaks or standing water.

▶Remove
standing water under cooling coils of air handling units by making sure that
drain pans slope toward the drain. Always use a pan tablet to prevent scum
deposits which can clog a condensate drain line. Consider installing a pan
tablet dispenser so the equipment owner can add pan tablets as needed.

Molds produce tiny spores to reproduce. Mold spores waft
through the indoor and outdoor air continually. When mold spores land on a damp
spot indoors, they may begin growing and digesting whatever they are growing on
in order to survive. There are molds that can grow on wood, paper, carpet and
foods. When excessive moisture or water accumulates indoors, mold growth will
occur, particularly if the moisture problem remains undiscovered or ignored.
There is no practical way to eliminate all molds and mold spores in the indoor
environment; the way to control indoor mold growth is to control
moisture and humidity.

The key to mold control is moisture control. It is
important to dry water-damaged areas and items within 24-48 hours to
prevent mold growth. If mold is a problem in a building, remove the mold, wet
materials and the excess water. Fix leaky plumbing or other sources of
water. Clean and kill mold on hard surfaces with a hard surface
cleaner that contains an EPA registered biocide (following label
instructions). Absorbent (porous) materials (such as fiberglass
insulation, fiber duct board, ceiling tiles and carpet) that become wet or
moldy must be replaced.

Black Mold, also known as Stachybotrys
Chartarum (atra) is a greenish-black fungus found worldwide that
colonizes particularly well in high-cellulose material, such as straw, hay, wet
leaves, dry wall, carpet, wall paper, fiber-board, ceiling tiles, thermal
insulation, etc. Back Mold (Stachybotrys Chartarum), before drying, is
wet and slightly slimy to touch. There are about 15 species of Stachybotrys
found worldwide.

This toxic mold grows in areas where the
relative humidity is above 55%. This type of fungus does not grow
on plastic, vinyl, concrete products, or ceramic tiles. It is not
found in the green mold on bread or the black mold on the shower tiles. The
toxic mold environmental risk may be one of the next major real estate
"due diligence" concerns, especially in property development areas
where major flooding has occurred.

The problem is that this mold can be found not only where
there has been flooding, but also in numerous minor water releases due to
plumbing failures, condensate overflow, condensation from cold refrigerant or
water lines, and water leaks and accidental water spills that were not cleaned
up within 48 hours. This toxic mold concern could also be a problem where fires
occurred, due to the massive amount of water normally used to extinguish a
building fire.

It is important to keep in mind that mold is only
a toxic risk or hazard if a person breathes or comes into contact with the mold
or the spores. Wet mold is not an indoor air quality health risk, but there is
a significant potential for the mold to dry and then be release into the air.

There may be a visual appearance of black mold in a visible
water damage area, but be aware that there may be hidden water damage and mold
(i.e., behind dry wall, under organic thread carpets). One should
suspect hidden mold if a building smells moldy, even if the source cannot be
seen, or if there has been water damage and residents are reporting health
problems. Humidifiers and condensate drain pans provide both a
growth medium and a distribution system for mold and mildew and should always
be inspected, cleaned with a hard surface cleaner that contains a biocide. Condensate
pan tablets should be used to prevent scum build-up in the condensate pan or
clogging of the condensate drain line (follow all label directions). Consider
adding a pan tablet dispenser.

In some cases, indoor mold growth may not be obvious. It is
possible that mold may be growing on hidden surfaces, such as the inside of
duct work that is wet, the back side of dry wall, wallpaper, or paneling, the
top of ceiling tiles, the underside of carpets and pads, etc. Possible
locations of hidden mold can include pipe chases and utility tunnels (with leaking
or condensing pipes), walls behind furniture (where condensation forms),
condensate drain pans inside air handling units, porous thermal or acoustic
liners inside ductwork, or roof materials above ceiling tiles (due to roof
leaks or insufficient insulation). Some building materials, such as dry wall
with vinyl wallpaper over it or wood paneling, may act as vapor barriers,
trapping moisture underneath their surfaces and thereby providing a moist
environment where mold can grow. It is important that building materials be
able to dry. Moisture should not be trapped between two vapor barriers or mold
may result.

Investigating hidden mold problems may be difficult and
require caution when the investigation involves disturbing potential sites of
mold growth (be sure to use personal protection equipment). For example,
the cleaning of moldy air ducts can lead to a massive release of spores from
mold growing in the ducts, and for this and other reasons, moldy porous air
ducts should always be replaced and not cleaned.

When addressing mold problems, remember to address the
source of the moisture problem, or the mold problem will simply reappear.
Remember to check for high humidity and condensation problems as well as actual
water leaks, maintenance issues, and HVAC system problems.

Molds can be found almost anywhere. They can grow
on virtually any organic substance, as long as moisture and oxygen are present.
There are molds that can grow on wood, paper, carpet, foods, and insulation.
When excessive moisture accumulates in buildings or on building materials, mold
growth will often occur, particularly if the moisture problem remains
undiscovered or ignored. It is impossible to eliminate all molds and mold
spores in the indoor environment. However, mold growth can be controlled
indoors by controlling moisture indoors.

Molds reproduce by making spores that usually cannot be seen
without magnification. Mold spores waft through the indoor and outdoor air
continually. When mold spores land on a damp spot indoors, they may begin
growing and digesting whatever they are growing on in order to survive. Molds
gradually destroy the things on which they grow.

Many types of molds exist. All molds have the potential to
cause health effects. Molds can produce allergens that can trigger allergic
reactions or even asthma attacks in people allergic to mold. Other molds are
known to produce potent toxins and/or irritants. Potential health concerns are
an important reason to prevent mold growth and to remediate/clean up any
existing indoor mold growth.

Since mold requires water to grow, it is important to
prevent moisture problems in buildings. Moisture problems can have many causes,
including uncontrolled humidity. Some moisture problems in buildings have been
linked to changes in building construction practices during the 1970s, 80s, and
90s. Some of these changes have resulted in buildings that are tightly sealed,
but may lack adequate ventilation, potentially leading to moisture buildup.
Building materials, such as drywall, may not allow moisture to escape easily.
Moisture problems may include roof leaks, landscaping or gutters that direct
water into or under the building, and un-vented combustion appliances. Delayed
maintenance or insufficient maintenance are also associated with moisture
problems in schools and large buildings. Moisture problems in portable
classrooms and other temporary structures have frequently been associated with
mold problems. When mold growth occurs in buildings, adverse health problems
may be reported by some building occupants, particularly those with allergies
or respiratory problems. Technicians should avoid exposing themselves and
others to mold-laden dusts while they conduct their cleanup activities.
Caution should be used to prevent mold and mold spores from being dispersed
throughout the air where they can be inhaled by building occupants.

Although there are many potential sources of indoor air
pollution, both research and field studies have shown that environmental
tobacco smoke (ETS) is one of the most widespread and harmful indoor air
pollutants. ETS is a combination of side stream smoke from the burning end of
the cigarette, pipe or cigar and the exhaled mainstream smoke from the smoker.
ETS contains over 4,000 chemicals; 43 of these chemicals are known animal or
human carcinogens (chemicals that are able to cause cancer when combined with
another substance). Numerous reports on smoking led to NIOSH (National
Institute for Occupational Safety and Health) recommendations that smoking
indoors be eliminated, or at least confined to designated areas.

Smoking areas must be separately ventilated,
negatively pressurized in relation to surrounding interior spaces, and supplied
with much more ventilation than non-smoking areas. The NIOSH bulletin further
recommends that the air from the smoking area should be exhausted directly
outdoors and not re-circulated within the building or vented with the general
exhaust for the building. ASHRAE Standard 62-1989 recommends
that smoking areas be supplied with 60 cubic feet per minute (60 cfm) of
outdoor air per occupant; the standard also recognized that using transfer air,
which is pulled in from other parts of the building, to meet the standard is
common practice.

Radon is an odorless and colorless
gas that emanates naturally from the earth and rock beneath building structures
and typically enters the structure from cracks in the foundation. Other sources
of radon include building materials manufactured from earth and rock (that
contain radon) and from well water. Radon is a gaseous radioactive element
having the symbol Rn, the atomic number 86, an atomic weight of 222, a melting
point of -71°C, and a boiling point of -62°C. It is an extremely toxic,
colorless gas; it can be condensed to a transparent liquid and to an opaque,
glowing solid; it is derived from the radioactive decay of radium and is used
in cancer treatment and in radiography.

Radon cannot be seen, smelled or
tasted, but it could be a problem in a building. The EPA has developed Radon
Zone Maps for each state. These maps were developed using five factors to
determine radon potential: indoor radon measurements; geology; aerial radioactivity;
soil permeability; and foundation type. These maps can be accessed at the EPA
website (http://www.epa.gov/radon/zonemap.html).

Radon is estimated to
cause many thousands of deaths each year since air containing radon may cause
lung cancer.In fact, the Surgeon General has warned that radon is the
second leading cause of lung cancer in the United States today.

A variety of methods
can be used to reduce radon in a structure. In some cases, sealing cracks in
floors and walls may help to reduce radon. In other cases, simple systems using
pipes and fans may be used to reduce radon. Such systems are called
"sub-slab depressurization", which do not require major changes to
the structure. These systems remove radon gas from below the concrete floor and
the foundation before it can enter the building. Similar systems can also be
installed in buildings with crawl spaces. Increased use of outside ventilation
air will also reduce radon levels inside the structure, and, in many cases, may
be the least expensive method and one which also solves various other IAQ
problems.

Health effects from indoor air pollutants may be experienced
soon after exposure or, possibly, years later.

Immediate effects may show up after a single
exposure or repeated exposures. These include irritation of the eyes, nose and
throat, headaches, dizziness and fatigue. Such immediate effects are usually short-term
and treatable. Sometimes the treatment is simply eliminating exposure to the
source of the pollution, if it can be identified. Symptoms of some diseases,
including asthma, hypersensitivity pneumonitis, and humidifier fever, may also
show up soon after exposure to some indoor air pollutants.

The likelihood of immediate reactions to indoor air
pollutants depends on several factors. Age and preexisting medical conditions
are two important influences. In other cases, whether a person reacts to a
pollutant depends on individual sensitivity, which varies tremendously from
person to person. Some people can become sensitized to biological pollutants
after repeated exposures, and it appears that some people can become sensitized
to chemical pollutants as well.

Certain immediate effects are similar to those from colds or
other viral diseases, so it is often difficult to determine if the symptoms are
a result of exposure to indoor air pollution. For this reason, it is important
to pay attention to the time and place the symptoms occur. If the symptoms fade
or disappear when a person is away from the building and return when the person
returns, an effort should be made to identify indoor air sources that may be
the possible cause. Some effects may worsen from an inadequate supply of
outdoor air or from the heating, cooling, or humidity conditions prevalent in
the building.

Other health effects may appear either years
after exposure has occurred or only after long or repeated periods of exposure.
These effects, which include some respiratory diseases, heart disease, and
cancer, can be severely debilitating or fatal. It is prudent to
improve the indoor air quality in the structure even if symptoms are not
noticeable.

While pollutants commonly found in indoor air are
responsible for many harmful effects, there is considerable uncertainty about
what concentrations or periods of exposure are necessary to produce specific
health problems. People also react very differently to exposure to indoor air
pollutants. Further research is needed to better understand which health
effects result after exposure to the average pollutant concentrations found in
buildings, and which result from the higher concentrations that occur for short
periods of time.

All molds have the potential to cause health effects. Molds
produce allergens, irritants, and, in some cases, toxins that may cause
reactions in humans. The types and severity of symptoms depend, in part, on the
types of mold present, the extent of an individual's exposure, the ages of the
individuals, and their existing sensitivities or allergies. Specific reactions
to mold growth can include the following:

Allergic Reactions: Inhaling or touching mold or
mold spores may cause allergic reactions in sensitive individuals. Allergic
reactions to mold are common - these reactions can be immediate or delayed.
Allergic responses include hay fever-type symptoms, such as sneezing, runny
nose, red eyes, and skin rash (dermatitis). Mold spores and fragments
can produce allergic reactions in sensitive individuals regardless of whether
the mold is dead or alive. Repeated or single exposure to mold or mold
spores may cause previously non-sensitive individuals to become
sensitive. Repeated exposure has the potential to increase sensitivity.

Asthma: Molds can trigger asthma attacks in
persons allergic (sensitized) to molds. The irritants produced by molds may
also worsen asthma in non-allergic (non-sensitized) people.

Hypersensitivity Pneumonitis: Hypersensitivity
pneumonitis may develop following either short-term (acute) or long-term
(chronic) exposure to molds. The disease resembles bacterial pneumonia and is
uncommon.

Irritant Effects: Mold exposure may cause
irritation of the eyes, skin, nose, throat, and lungs, and sometimes can create
a burning sensation in these areas.

Opportunistic Infections: People with weakened
immune systems (i.e., immune-compromised or immune-suppressed individuals) may
be more vulnerable to infections by molds (as well as more vulnerable than
healthy persons to mold toxins). Aspergillus fumigatus, for
example, has been known to infect the lungs of immune-compromised individuals.
These individuals inhale the mold spores, which then start growing in their
lungs. Trichoderma has also been known to infect
immune-compromised children. Healthy individuals are usually not vulnerable to
opportunistic infections from airborne mold exposure. However, molds can cause
common skin diseases, such as athlete's foot, as well as other infections such
as yeast infections.

A major concern with mold is that the mold can be hidden
behind walls and deep in air ducts making it difficult to remove all the
mold from the structure. Diligence should be exerted to remove and
dispose of any porous materials that have been contaminated by mold because
they cannot be cleaned effectively. However, hard non-porous ductwork and
other surfaces can be cleaned with a hard surface cleaner. Section
III Treatment of IAQ Problems provides greater details on the various
treatment methods.

Currently, most health organizations consider exposure to
Stachybotrys mold as a health hazard. Also, keep in mind that most responses
leading to testing, investigations, and abatement of the Stachybotrys toxic
mold are due directly to occupant complaints or documented detrimental health
effects. Stachybotrys mold may evolve to a point where it is regarded with the
same caution, response and liability concerns as those attributed to lead-base
paint and asbestos. Health hazards and risks associated with concern to
exposure to Stachybotrys are currently considered as short-term effects.
Alternatively, exposure to radon gas in buildings is considered a long-term
health risk and is not considered a short-term hazard.

Molds can produce toxic substances called mycotoxins. Some
mycotoxins cling to the surface of mold spores; others may be found within
spores. More than 200 mycotoxins have been identified from common molds, and
many more remain to be identified. Some of the molds that are known to produce
mycotoxins are commonly found in moisture-damaged buildings. Exposure
pathways for mycotoxins can include inhalation, ingestion, or skin contact.
Although some mycotoxins are well known to affect humans and have been shown to
be responsible for human health effects, for many mycotoxins, little
information is available. The information on the human health effects of
inhalation exposure to mycotoxins (which is available) is typically derived
from studies performed in the workplace. Information on ingestion exposure, for
both humans and animals, is more abundant--a wide range of health effects has
been reported following ingestion of moldy foods including liver damage,
nervous system damage, and immunological effects.

Many symptoms and human health effects attributed to
inhalation of mycotoxins have been reported, including: mucous membrane
irritation, skin rash, nausea, immune system suppression, acute or chronic
liver damage, acute or chronic central nervous system damage, endocrine
effects, and cancer. More studies are needed to clarify the health effects
related to most mycotoxins. However, it is clearly prudent to avoid exposure to
molds and mycotoxins.

Some molds can produce several toxins, and some molds
produce mycotoxins only under certain environmental conditions. The presence of
mold in a building does not necessarily mean that mycotoxins are present or
that they are present in large quantities.

Aflatoxin B1 is perhaps the most well-known
and studied mycotoxin. It can be produced by the molds Aspergillus
flavus and Aspergillus parasiticus and it is one of
the most potent carcinogens known. Ingestion of aflatoxin B1 can
cause liver cancer. There is also some evidence that inhalation of aflatoxin B1 may
cause lung cancer. Aflatoxin B1 has been found on contaminated
grains, peanuts and other human and animal foodstuffs. However, Aspergillus
flavus and Aspergillus parasiticus are not
commonly found on building materials or in indoor environments.

Aspergillus versicolor and Stachybotrys
atra (chartarum), are known to produce potent toxins under certain
circumstances. Stachybotrys produces a mycotoxin that causes animal and human
mycotoxicosis. This type of mold is thought to be a possible cause of the
"sick building syndrome". In May 1997, The Journal of the
American Medical Association carried a news article titled
"Floods carry potential for toxic mold disease". Children's exposure
to air-borne Stachybotrys spores is thought to most likely cause pulmonary hemorrhage
(bleeding in the lungs). Please be aware that there is no threshold dangerous
spore exposure level established by the U.S. EPA or any other health
administrations. There are ongoing epidemiology studies being conducted. There
is reference information related to a 1994 incident in Cleveland, Ohio, where
45 cases of pulmonary hemorrhage in young infants occurred. Sixteen of the
infants died. In addition, many departments of health administration in states
across the U.S., as well as the Center for Disease Control (CDC), list the
following as symptoms associated with exposure to Stachybotrys mold spores:

Some compounds produced by molds are volatile and are
released directly into the air. These are known as microbial volatile organic
compounds (mVOCs). Because these compounds often have strong and/or unpleasant
odors, they can be the source of odors associated with molds. Exposure
to mVOCs from molds has been linked to symptoms such as headaches, nasal
irritation, dizziness, fatigue and nausea. Research on mVOCs is still in the
early phase.

Glucans are small pieces of the cell walls of molds that may
cause inflammatory lung and airway reactions. These glucans may affect the
immune system when inhaled. Exposure to very high levels of
glucans or dust mixtures, including glucans, may cause a flu-like illness known
as Organic Dust Toxic Syndrome (ODTS). This illness has been primarily noted in
agricultural and manufacturing settings.

Mold spores are microscopic (2-10 µm) and are
naturally present in both indoor and outdoor air. Molds reproduce by means of
spores. Some molds have spores that are easily disturbed and waft into the air
and settle repeatedly with each disturbance. Other molds have sticky spores
that cling to surfaces and become dislodged by brushing against them or by
other direct contact. Spores may continue to grow for years after they are
produced. In addition, whether or not the spores are alive, the
allergens in and on them may remain allergenic for years.

Radon gas decays into radioactive particles that may become
trapped in the lungs as a person breathes. As they break down further, these
particles release small bursts of energy. This could damage lung tissue and
lead to lung cancer over the course of one's lifetime. Not everyone exposed to
elevated levels of radon will develop lung cancer, and the amount of time
between exposure and the onset of the disease may be many years.

Like other environmental pollutants, there is some
uncertainty about the magnitude of radon health risks. However, we know more
about radon risks than risks from most other cancer-causing substances. This is
because estimates of radon risks are based on studies of cancer in humans
(underground miners, for example). Additional studies on more typical
populations are under way. Smoking combined with radon is an especially serious
health risk.

Children are reportedly at greater risk than adults of
certain types of cancer from radiation, but there is currently no conclusive
data on whether children are at greater risk than adults from radon.

Groups that may be particularly susceptible to the effects
of indoor air contaminants include, but are not limited to:

▶Allergic
or asthmatic individuals

▶People
with respiratory disease

▶People
whose immune systems are suppressed due to chemotherapy, radiation therapy, or
diseases from other causes

▶Contact
lens wearers

The effects of IAQ problems are often non-specific symptoms
rather than clearly defined illnesses. Symptoms commonly
attributed to IAQ problems include headache, fatigue, sinus congestion, cough,
sneezing, dizziness and nausea. All of these symptoms, however, may also be
caused by other factors, and are not necessarily due to air-quality
deficiencies.

"Health" and "comfort" are used to
describe a spectrum of physical sensations. For example, when the air in a room
is slightly too warm for a person's activity level, that person may experience
mild discomfort. If the temperature continues to rise, discomfort increases and
symptoms such as fatigue, stuffiness and headaches may appear.

The term,Sick
Building Syndrome (SBS), is sometimes used to describe cases in which building
occupants experience acute health and comfort effects that are apparently
linked to the time they spend in the building, but in which no specific illness
of cause can be identified. The complaints may be localized to a particular
room or zone, or may be widespread throughout the building. Many different
symptoms have been associated with SBS, including respiratory complaints,
irritation and fatigue.Analysis of air samples often fails to detect high
concentrations of specific contaminants.
The problem may be caused by any or all of the following:

▶Building
Related Illness (BRI) refers to illness caused by exposure to the building air,
where symptoms of diagnosable illnesses are identified (e.g., certain allergies
or infections) and can be directly attributed to environmental agents in the
air. Legionnaire's Disease and hypersensitivity pneumonitis are examples of BRI
that can have serious, even life threatening, consequences

▶A
small percentage of the population may be sensitive to a number of chemicals in
indoor air, each which may occur at very low concentrations. The existence of
this condition, which is known as Multiple Chemical Sensitivity (MCS), is a
matter of controversy. MCS is not currently recognized by the major medical
organizations, but medical opinion is divided, and further research is needed

Section
II:

Usually the most effective way to improve indoor air quality
is to eliminate individual sources of pollution or to reduce their emissions.
Some sources, like those that contain asbestos, can be sealed or enclosed;
others, like gas stoves, can be adjusted to decrease the amount of emissions.
In many cases, source control is also a more cost-effective approach to
protecting indoor air quality than increasing ventilation which may increase
energy costs. Specific sources of indoor air pollution in a building are listed
later in this section. For most indoor air quality problems in the building,
source control is the most effective solution.

Most commercial air-handling units distribute a blend of
outdoor air and recirculated indoor air. HVAC designs may also include units
that introduce 100% outdoor air or that simply transfer air within the
building. Uncontrolled quantities of outdoor air enter buildings through
windows, doors and gaps in the exterior construction.

Thermal comfort and ventilation needs are met by supplying
"conditioned" air (a blend of outdoor and recirculated air that has
been filtered, heated or cooled, and sometimes humidified or dehumidified.)
Large buildings often have interior ("core") spaces in which constant
cooling is required to compensate for heat generated by occupants, equipment,
and lighting, while perimeter rooms may require heating or cooling depending on
outdoor conditions.

One technique for controlling odors and
contaminants is to dilute them with outdoor air. Dilution can work only if
there is a consistent and appropriate flow of supply air that mixes effectively
with room air. The term "ventilation efficiency" is used to describe
the ability of the ventilation system to distribute supply air and remove
internally generated pollutants. Researchers are currently exploring ways to
measure ventilation efficiency and interpret the results of those measurements.

Another technique for isolating odors and contaminants is to
design and operate the HVAC system so that pressure relationships between rooms
are controlled. This control is accomplished by adjusting the air quantities
supplied to and removed from each room. If more air is supplied to a room than
is exhausted, the excess air leaks out of the space and the room is said to be
under positive pressure. If less air is supplied than is exhausted, air is
pulled into the space and the room is said to be under negative pressure.

A third technique is to use local exhaust systems (sometimes
known as dedicated exhaust ventilation systems) to isolate and remove
contaminants by maintaining negative pressure in the area around the
contaminant source. Local exhaust can be linked to the operation of a
particular piece of equipment (such as kitchen range) or used to treat an
entire room (such as a smoking lounge or custodial closet). Air should be
exhausted to the outdoors, not recirculated, from locations that produce
significant odors and high concentrations of contaminants (such as copy rooms,
bathrooms, kitchens and beauty salons).

Spaces where local exhaust is used must be provided with
make-up air and the local exhaust must function in coordination with the rest
of the ventilation system. Under some circumstances, it may be acceptable to
transfer conditioned air from relatively clean parts of a building to
comparatively dirty areas and use it as make-up air for a local exhaust system.
Such a transfer can achieve significant energy savings.

Air cleaning and filtration devices designed to control
contaminants are found as components of HVAC systems (for example, filter boxes
in ductwork) and can also be installed as independent units. The effectiveness
of air cleaning depends upon proper equipment selection, installation,
operation and maintenance. Caution should be used in evaluating the
many new technological developments in the field of air cleaning and
filtration.

One approach to lowering the concentrations of indoor air
pollutants in a structure is to increase the amount of outdoor air coming
indoors. Most building heating and cooling systems, including forced air
heating or cooling systems, do not mechanically bring fresh air into the
houses, whereas commercial buildings typically have a means to mechanically
draw fresh air into the structure. ASHRAE Standard 62.2 represents the minimum
requirements for residential ventilation and acceptable indoor air quality. Best
or good practice may require going beyond those minima. Traditionally,
residential ventilation has been provided by natural ventilation and
infiltration. Sherman and Matson (1997) showed that most older buildings are
leaky enough so that infiltration (air leaks from outside) alone can meet the
minimum requirements of ASHRAE Standard 62.2. However, houses built to new
standards have substantially tighter envelopes and there is insufficient
infiltration to meet even the minimum ventilation standards. Furthermore,
simply meeting the minimum standard is not always sufficient to adequately
dilute all contaminants.

For today's modern, single-family dwellings a whole-house
mechanical ventilation system may be necessary when individuals with allergies
or chemical sensitivities occupy the building or when there are unusual sources
of impurities. Advanced designs of new buildings are featuring mechanical
systems that bring outdoor air into the building. Some of these designs include
energy-efficient heat recovery ventilators (also known as air-to-air heat
exchangers). Typical total ventilations requirements are at least the larger of
7.5 CFM per person (based on Normal Occupancy) and 1 CFM per 100 square feet of
floor space. The intermittent exhaust flow rates for kitchens are 100 CFM and
50 CFM for utility rooms, bathrooms, etc. The continuous exhaust flow rate for
kitchens is five air changes per hour and 20 CFM for utility rooms, bathrooms,
etc.

As air is circulated through the
structure via heating, ventilating, and/or air conditioning (HVAC) systems,
particulate matter will accumulate inside the system where, especially in
cooling systems, they serve as medium for bacteria and fungal growth. The
dispersion of microbes such as bacteria, virus, mold, and fungus can be the
source of sickness to exposed occupants in the climate-controlled area. For
example, Legionella pneumophilia has been found to exist in such an environment
and has been linked to Legionnaire's disease. Other microbes may contribute to
"sick building" or "sick building" syndrome. Many people
are also allergic to the molds and fungus entrained in the dwelling's
ventilation system as the air passes over contaminated condensate drain water
and wet evaporator cooling coils. For this reason, it is very important
that evaporator coils be cleaned and disinfected at least once per cooling
season and the condensate pan be treated with a biocide to stop the breading of
bacteria, virus, mold and fungus, which can be entrained into the conditioned
air and carried throughout the building.

There are many types and sizes of air cleaners on the
market, ranging from relatively inexpensive tabletop models to sophisticated,
expensive whole-building systems. Some air cleaners are highly effective at
particle removal, while others, including most tabletop models, are much less
so. Air cleaners are generally not designed to remove gaseous pollutants.

The effectiveness of an air cleaner depends on how
well it collects pollutants from indoor air (expressed as a percentage
efficiency rate) and how much air it draws through the cleaning or filtering
element (expressed in cubic feet per minute). A very efficient collector with a
low air-circulation rate will not be effective, nor will a cleaner with a high
air-circulation rate with a less efficient collector. The long-term performance
of any air cleaner depends on maintaining it according to the manufacturer's
directions.

At present, EPA does not recommend using air cleaners to
reduce levels of radon and its decay products. The effectiveness of these
devices is uncertain because they only partially remove the radon decay
products and do not diminish the amount of radon entering the building. EPA
plans to additionally research whether air cleaners are, or could become, a
reliable means of reducing the health risk from radon.

Types of air cleaners or air filtration include:

▶Mechanical
filters, including, the typical furnace or AC filter

▶Electronic
air cleaners (for example, electrostatic precipitators) which trap charged
particles using an electrical field

▶Ion
generators that act by charging the particles in a room. The charged particles
are then attracted to walls, floors, draperies, etc., or a charged
collector

▶"Hybrid"
devices, which contain two or more of the particle removal devices discussed
above

There are essentially two methods to purify or
filter the air, mechanical filtration and electrostatic filtration. With
mechanical filtration, a filter permits air to pass through a porous, typically
fiber-like, material that essentially blocks the path and ideally captures
these particles. Since the pores between fibers are typically larger than the
airborne particles the filter relies on the random chance that the particle
will get caught on a fiber. If the thickness of the filter is increased
or the pores are made smaller through the use of a tighter fiber weave, then
the resistance to the passage of air increases, thereby increasing the pressure
loss, reducing the airflow and ultimately decreasing the system's cooling
capacity and efficiency.

An alternate method designed for the purpose of
increasing particulate removal efficiency without decreasing pore size or
increasing fiber density is electrostatic attraction. Active
electrostatic filters, commonly referred to as electronic air filters, impart a
high-voltage charge between plates and any charged particles passing through
are electrostatically withdrawn from the passing air and captured on the
charged collection plate. This type of electrostatic system (discussed in the
next subsection) normally suffers from a rapid decrease in performance as the
collection plate becomes dirty and therefore insulated.

To alleviate the need for an applied voltage but
still obtain the advantages of electrostatic dust removal, passive
electrostatic systems have been developed. A passive electrostatic system
relies on dielectric (non-conducting) fibers that harbor electrostatic charges
produced from air friction as the air is drawn through the filter. Air passing
through dielectric fibers generates friction that induces a static charge that
builds up to become substantial enough to draw out any passing charged
particles, namely dust. This is the principal behind electrostatic filters used
in HVAC systems. The passive electrostatic filter behaves similarly to active
electrostatic filters whereby dust is drawn from the air and attracted to the
fibers by electrostatic forces this time without the need for external
electrical power. Typically, because of their high cost, this type of passive
electrostatic filter is cleaned and reused rather than discarded when dirty. However,
by their nature, theses filters are difficult to get perfectly clean and their
performance degrades after the first use. There are also disposable
electrostatic filters, however, in most cases, a careful inspection of the
package will reveal that these disposable filters are not fabricated from 100%
electrostatic fibers but instead only contain some electrostatic fibers,
thereby making their effectiveness questionable.

Mainstream's PuraClean® Filter Spray has
been demonstrated to be an alternative to electrostatic filters, and can be
applied to ordinary disposable filters. PuraClean® Filter Spray
creates a passive low-cost electrostatic filter from an ordinary low-cost
disposable filter. In this way the low-cost filter could be disposed instead of
cleaned. PuraClean® is a liquid formulation, which, after
application to an ordinary non-electrostatic filter (such as a metallic filter,
disposable spun-glass filter, or foam filter), will produce a dielectric filter
surface (insulating surface) and transform an ordinary filter into a passive
electrostatic filter.

The only true measure of a filter's effectiveness
is the Minimum Efficiency Reporting Value (MERV). Most filters
are labeled with a MERV rating number, which measures a filter's ability to
trap particles ranging in size from 3.0 microns to 10.0 microns. Residential
filters commonly have MERV ratings of 1-12. The higher the MERV rating, the
more efficient the filter is and the more particles it can filter.

MERV is an industry standard
rating, so it can be used to compare filters made by different companies.

▶A
MERV rating of 6 means the filter is 35% to 50% minimum efficient at capturing
the measured particles

▶A
MERV rating of 8 means the filter is 70% to 85% minimum efficient at capturing
the measured particles

▶A
MERV rating of 11 means the filter is 85% to 95% minimum efficient at capturing
the measured particles

When sprayed on typical disposable
filters,PuraClean®Filter Spray demonstrates an increase of up to 300% in
particle capture,with no significant increase in pressure drop.In ASHRAE 52.2 testing, the MERV rating of
non-electrostatic filters improved by as much as 65% by using PuraClean®, see Figure 1.PuraClean®'s
technology garners these dramatic results by converting non-electrostatic
surfaces into electrostatic surfaces. A more efficient filter also means the
evaporator coil will stay cleaner, which translates into improved energy
efficiency and improved cooling capacity.

There are a number of companies that offer Electronic
Air Cleaners. These devices have a positively or negatively charged grid that
charges the contaminants in the air and an oppositely charged or grounded
collection surface to which the contaminants are attracted. These filters have
very good initial filtration effectiveness and very little pressure drop, but
the filtration efficiency decreases rapidly due to build-up on the collection
plate, which essentially insulates the collection plate and stops the
filtration. Also, as the collection plate becomes insulated,
the charged contaminants are then attracted to other grounded surfaces, such as
walls, ceilings, furniture, etc., thereby causing staining of these surfaces

Over the past few years, there has been some publicity
suggesting that houseplants have been shown to reduce levels of some chemicals
in laboratory experiments. There is currently no evidence,
however, that a reasonable number of houseplants remove significant quantities
of pollutants in buildings and offices. Indoor houseplants should not be
over-watered because overly damp soil may promote the growth of microorganisms
that may affect allergic individuals.

▶Ion
generators and electronic air cleaners may produce ozone, particularly if they
are not properly installed and maintained. Ozone can be a lung irritant

▶Gases
and odors from particles collected by the filtration device, and remain on the
filter in the airflow, may be re-dispersed into the air

▶The
odor of tobacco smoke is largely due to gases in the smoke, rather than
particles. Thus, one may smell a tobacco odor even when the smoke particles
have been removed

▶Some
devices scent the air to mask odors, which may lead you to believe that the
odor-causing pollutants have been removed

▶Ion
generators, especially those that do not contain a collector, or that have a
dirty collector, can cause soiling of walls and other surfaces

▶Maintenance
costs, such as costs for the replacement of filters, may be significant in
certain systems

▶Several
brands of ozone generators have an establishment number on their packaging. This
number helps EPA identify the specific facility that produces the product. To
quote the EPA from their website: "The display of this number does not
imply an EPA endorsement or suggest in any way that the EPA has found the
product to be either safe or effective."

Preventing Duct
Contamination

Use PuraClean® Filter Spray on all HVAC filters
and instruct the building owner how to use PuraClean® on the filters
when it's time to change them. It's important to change air filters monthly and
apply PuraClean® with every filter change. We suggest an offer to
sell customers a six-month or a year's supply (depending on whether annual or semiannual
tune ups are done) of both filters and PuraClean®during the
discussion of the services performed and before preparing
the final bill for services and supplies. Filters must be changed monthly, even
more frequently if they are severely loaded up with contaminants during monthly
filter replacements. Explain that any contaminants removed from the conditioned
air by the filter are being kept from their lungs! PuraClean®
treated filters are capable of removing mold spores, in addition to dust mites
and bacteria. Remember that removing moisture is the first line of defense, and
a clean environment, provided by good filtration is the second line of defense.
Improved filtration will also minimize the amount of dusting needed in the
building. Of course, no filtration of any type will remove harmful gasses, such
as carbon monoxide, or are effective at removing radon from the air.

When performing any service of a structure's
heating or cooling system, always recommend the additional service work of
cleaning cooling coils and drain pains for cooling systems, as well as the heat
exchangers and humidifiers of heating systems. This is the most economical way
for building owners to potentially avoid future IAQ problems.

Moisture should not be present in
ducts. Controlling moisture is the most effective way to
prevent biological growth in air ducts.

Moisture can enter the duct system through leaks or if the
system has been improperly installed or serviced. Research
suggests that condensation (which occurs when a surface temperature is lower
than the dew point temperature of the surrounding air) on or near cooling coils
of air conditioning units is a major factor in moisture contamination of the
system. The presence of condensation or high relative humidity is an important
indicator of the potential for mold growth on any type of duct.

Controlling moisture can often be difficult, but here are
some steps to take:

▶Repair
any leaks or water damage promptly and properly. Discard any wet insulation or
fiber duct board; it cannot be effectively dried.

▶Pay
particular attention to cooling coils, which are designed to remove water from
the air and can be a major source of moisture contamination of the system,
leading to mold growth. If mold is present, clean the hard surfaces of the air
handler and the evaporator coils with a hard surface cleaner (ideally one that
contains an EPA registered biocide). Make sure the condensate pan drains
properly. The presence of substantial standing water and/or debris indicates a
problem requiring immediate attention. Check any insulation near cooling coils
or wet spots. Treat all drain pans with pan tablets.

▶Ensure
all ducts are properly sealed and insulated in all non-air-conditioned spaces
(e.g., attics and crawl spaces). This will help prevent moisture due to
condensation from accumulating on the duct work or entering the system. To
prevent water condensation, the cooling system and associated duct work must be
properly insulated.

▶Verify
that the AC unit is operating properly. Humidity must be maintained below 55%
(ideally 30% to 50%). If humidity is a problem, consider installing a
dehumidifier.

Concern about indoor exposure to mold has increased as the
public becomes aware that exposure to mold can cause a variety of health
effects and symptoms, including allergic reactions.

Molds gradually destroy the things they grow on. The simple
way to prevent damage to building materials and furnishings, save money, and
avoid potential health risks caused by mold formation is to control moisture
and thereby eliminate mold growth. The key to mold control is moisture
control.

Molds are part of the natural environment. Outdoors, molds
play a part in nature by breaking down dead organic matter, such as fallen
leaves and dead trees, but indoors, mold growth should be avoided. Molds reproduce
by means of tiny spores; the spores are invisible to the naked eye and float
through outdoor and indoor air. Mold may begin growing indoors when mold
spores land on surfaces that are wet. There are many types of
mold but none of them will grow without water or moisture.

Molds spores are usually not a problem indoors, unless these
mold spores land on a wet or damp spot and begin growing into mold. Molds have
the potential to cause health problems. Molds produce allergens (substances
that can cause allergic reactions), irritants, and in some cases, potentially
toxic substances (mycotoxins). Inhaling or touching mold or mold spores may
cause allergic reactions in sensitive individuals. Allergic responses include
hay fever-type symptoms, such as sneezing, runny nose, red eyes, and skin rash
(dermatitis).

Allergic reactions to mold are common. They can be immediate
or delayed. Molds can also cause asthma attacks in people with asthma who are
allergic to mold. In addition, mold exposure can irritate the eyes, skin, nose,
throat, and lungs of both mold-allergic and non-allergic people. Symptoms other
than the allergic and irritant types are not commonly reported as a result of
inhaling mold. Research on mold and health effects is ongoing.

Standards or Threshold Limit Values (TLVs) for
airborne concentrations of mold or mold spores have not been set. Although U.S.
EPA has no regulations or health standards for airborne mold contaminants, in
June 2002, Congressman John Conyers, Jr. of Michigan introduced H.R. 5040 to
Congress, which is called the United States Toxic Mold
Safety and Protection Act of 2002, or the "Melina Bill."

Title I of this pending legislation directs U.S. EPA,
The Centers for Disease Control and Prevention (CDC), and
the National Institutes of Health (NIH) to jointly study the
health effects of indoor mold growth to determine, among other things,
"minimum levels of exposure at which indoor mold growth is harmful to
human health." In addition, U.S. EPA has prepared numerous guidance
documents on the topics of indoor air quality and mold in buildings of all
sizes.

The state of California has adopted mold-related
legislation, New York City has developed guidelines for indoor mold assessment
and remediation, and Canada has prepared a comprehensive guide to recognition
and management of fungal contamination in public buildings. In addition,
microbiological research on the health effects of mold is under way in the
United States, Canada, the United Kingdom, the Netherlands and Sweden.

The key to mold control is moisture control.
Solve moisture problems before they become mold problems!

▶Fix
leaky plumbing and leaks in the building envelope as soon as possible.

▶Watch
for condensation and wet spots. Fix sources of moisture problems as soon as
possible.

▶Prevent
moisture due to condensation by increasing surface temperature or reducing the
moisture level in air (humidity). To increase surface temperature, insulate or
increase air circulation. To reduce the moisture level in air, repair leaks,
increase ventilation (if outside air is cold and dry), or dehumidify (if
outdoor air is warm and humid).

▶Keep
heating, ventilation, and air conditioning (HVAC) drip pans clean, flowing
properly, and unobstructed. Use pan tablets to help prevent deposits that can
clog drain lines.

▶Vent
moisture-generating appliances, such as dryers, to the outside where
possible.

Section III:

Some health effects can be useful indicators of an indoor
air quality problem, especially if they appear after a person moves to a new
residence, remodels or refurnishes a building, or treats a building with
pesticides. If occupants have symptoms that may be related to
their indoor environment, they should discuss these symptoms with their doctor
or the local health department to see if they could be caused by indoor air
pollution. They may also want to consult a board-certified allergist or an
occupational medicine specialist for answers to their questions.

Another way to judge whether a building has or could develop
indoor air problems is to identify potential sources of indoor air pollution.
Although the presence of such sources does not necessarily mean that there is
an indoor air quality problem, being aware of the type and number of potential
sources is an important step toward assessing the air quality in a building.

A third way to decide whether an environment may have poor
indoor air quality is to evaluate at the activities occurring in the location.
Human activities can be significant sources of indoor air pollution. Also, look
for signs of problems with the ventilation. Signs that can indicate inadequate
or improper ventilation include moisture condensation on windows or walls,
smelly or stuffy air, dirty central heating and air conditioning equipment, and
areas where books, shoes, or other items become moldy.

The federal government recommends
measuring the level of radon in structures. Without measurements, there is no
way to tell whether radon is present because it is a colorless, odorless,
radioactive gas. Inexpensive devices are available for measuring radon. EPA
provides guidance as to risks associated with different levels of exposure and
when the public should consider corrective action. There are specific
mitigation techniques that have proven effective in reducing levels of radon in
the building.

For pollutants other than radon,
measurements are most appropriate when there are either health symptoms or
signs of poor ventilation andspecific sources or pollutants have been identified as
possible causes of indoor air quality problems. Testing for many pollutants can be expensive. Before
monitoring a structure for pollutants besides radon, consult the state or local
health department.

The intent of the walkthrough
inspection is to acquire a good overview of occupant activities and building
functions, and to look for IAQ problem indicators. Odors in inappropriate
locations (e.g., kitchen odors in a lobby) may indicate that ventilation system
components require adjustment or repair.

The walkthrough inspection can be
used to identify areas with a potential for IAQ problems.The
following are general indicators of IAQ problems:

Signs of occupant discomfort: Notice uneven
temperatures, persistent odors, drafts, and sensations of stuffiness. It is
possible that occupants are attempting to compensate for an HVAC system that
does not meet their needs. Look for propped-open corridor doors, blocked or taped
up diffusers, popped up ceiling tiles, people using individual fans/heaters or
wearing heavier/lighter clothing than normal.

Overcrowding: Future occupant density is
estimated when the ventilation system for a building is designed. When the
actual number of occupants approaches or exceeds this occupant design capacity,
IAQ complaints may increase. At that point, the outdoor air ventilation rate
will have to be increased. However, the ventilation and cooling systems may not
have sufficient capacity to handle the increased loads from the current use of
space.

Blocked airflow: Check for under-ventilation
caused by obstructed vents, faulty dampers or other HVAC system malfunctions,
or from problems within occupied space. Furniture, papers, or other materials
can interfere with air movement around thermostats or block airflow from wall
or floor-mounted registers. If office cubicles are used, a small space (2 to 4
inches) between the bottom of the partitions and the floor may improve air
circulation.

Ceiling plenums: Lift a ceiling tile and examine
the plenum for potential problems. Walls or full-height partitions that extend
to the floor above can obstruct or divert air movement in ceiling plenums
unless transfer grilles have been provided. If fire dampers have been installed
to allow air circulation through walls or partitions, confirm that the dampers
are open. Construction debris and damaged or loose material in the plenum area
should be removed.

Heat Sources: Be aware of areas that contain
unusual types or quantities of equipment such as copy machines or computer
terminals. Also, look for instances of over illumination. High concentrations
of electrical fixtures and equipment can overwhelm the ventilation and cooling
systems.

Special use areas: Confirm that the HVAC system
maintains appropriate pressure relationships to isolate and contain odors and
contaminants in mixed-use buildings and around special use areas. Examples of
special use areas include attached parking garages, loading docks, print shops,
smoking lounges, janitorial closets, storage areas and kitchens.

Improperly located vents, exhausts and air intakes: Check
the outdoor air intakes to see whether they are located near contaminant
sources (e.g., plumbing vents, exhaust outlets, dumpsters, loading docks or
other locations where vehicle engines run idle).

Unsanitary mechanical rooms: See if the space
containing the HVAC system is clean and dry. Examples of problems include
cleaning or other maintenance supplies stored in mechanical room; dust and dirt
buildup on floors and equipment; and moisture in mechanical rooms because of
inadequate insulation, lack of conditioned air, or failure to provide for air
movement. Unsanitary conditions in a mechanical room are particularly
problematic if un-ducted return air is dumped into and circulated through a
mechanical room.

Humidity is something we hear
about daily in weather reports. Humidity is to blame for that muggy, steam-room
feeling experienced on certain summer days. Humidity can be measured in several
ways, but relative humidity is the most common. In order to understand relative
humidity, it is helpful to first understand absolute humidity.

Absolute humidity is the mass of water
vapor divided by the mass of dry air in a volume of air at a given temperature.
The hotter the air is, the more water it can contain.

Relative humidity is the ratio of
the current absolute humidity to the highest possible absolute humidity (which
depends on the current air temperature). A reading of 100 percent relative
humidity means that the air is totally saturated with water vapor and cannot
hold any more water vapor.

Individuals are very sensitive to
humidity; the body relies on the evaporation of sweat to provide cooling for
the body. The process of sweating is the body's attempt to keep cool and
maintain its current temperature. If the air is at 100-percent relative
humidity, sweat will not evaporate into the air. As a result, a person may feel
much hotter than the actual temperature when the relative humidity is high. If
the relative humidity is low, we feel much cooler than the actual temperature
because our sweat evaporates easily and cools us off.

People tend to feel most
comfortable at a relative humidity of about 45%. To avoid any mold problems, it
is recommended that theindoor
humidity always be maintained below 55% (ideally between 30% and 50%) relative
humidity.

The simplest method of determining
the relative humidity is to measure the wet bulb and dry-bulb air temperatures
inside the structure and use a Psychrometric Chart (Figure
2) to determine the relative humidity. The
relative humidity is determined from the intersection of the appropriate wet
and dry bulb temperatures that are measured in the structure. Both temperature
measurements must be made at the same location and it is the relative humidity
at that location which is obtained. Figure 2 contains a small chart for normal sea-level elevation;
similar charts have also been prepared for other altitudes. ASHRAE
Fundamentals, as well as many air conditioning handbooks, contain a complete
set of Psychrometric Charts.

At first glance, a psychrometric chart appears complex;
however, by separating the various lines and scales on the chart, the use of
the chart can be easily described. The four steps for determining the relative
humidity from a Psychrometric Chart are described below:

Step 1. Measure the dry-bulb
and wet-bulb air temperatures

Dry-bulb air temperature is the air temperature determined
by an ordinary thermometer or thermocouple. Alternatively, the wet-bulb
temperature reflects the cooling effect of evaporating water. Wet-bulb temperature
can be determined by passing air over a thermometer whose bulb (the base of the
thermometer) is wet (the bulb has been wrapped with a small amount of moist
cloth). If a thermocouple is used, instead of a thermometer, the sensor tip of
the thermocouple is wrapped with a moist cloth. The cooling effect of the
evaporating water causes a lower temperature compared to the dry bulb air
temperature. To get an accurate wet-bulb temperature, the air must blow past
the wet-bulb thermometer; using a fan to blow the air, or using a sling
psychrometer can accomplish this.

The sling psychrometer consists of two thermometers mounted
side-by-side on a holder which can be whirled through the air. The dry-bulb
thermometer is bare and the wet-bulb thermometer is covered by a wick (cloth)
that is kept wet with clean water. After being whirled for a sufficient time,
the wet-bulb thermometer reaches its equilibrium point (reaches a steady value)
and both the wet- and dry-bulb temperatures can be read. Readings should be
taken as quickly as possible. Rapid movement of the air past the wet-bulb is
necessary to get dependable readings. Figure 3
shows a simple sling psychrometer.

Step 3. Find the location of
the measured wet-bulb air temperature on the Psychrometric Chart.

Wet-bulb temperature reflects the cooling effect
of evaporating water. The wet-bulb temperature scale is located along the
curved upper left portion of the chart. The sloping lines indicate equal
wet-bulb temperatures. See Figure 5 below.

Step 4. Determine the Relative
Humidity as the intersection of the wet-bulb and dry-bulb air temperature
lines.

Lines representing conditions of equal relative humidity
sweep from the lower left to the upper right of the Psychrometric Chart, as
shown in Figure 6. The 100% relative humidity
(saturation) line is also the Dew Point line. The line for zero percent
relative humidity falls along the dry-bulb temperature scale line. Therefore,
to determine the Relative Humidity, the intersection of wet-bulb and dry-bulb
temperature lines is found on the Psychrometric Chart and then the relative
humidity is read off the chart at this location.

For example, with a measured 80°F dry-bulb temperature and
67°F wet-bulb temperature as shown in Figure 7, the
relative humidity is 50%. Also, note that the dew point for this case is 60°F,
which means any surface in the building whose surface is below 60°F, such as a
poorly insulated AC line or duct work will condense moisture from the air
(sweat) and will be a site for mold growth. This is why air ducts and
refrigeration lines must be completely insulated.

The versatility of the psychrometric chart lies in the fact
that by knowing just two properties of moist air, the other properties can be
determined. Therefore, if there are some cool surfaces that cannot be insulated
and must not condense water, such as cold water lines inside the floor of the
structure, the dew point temperature and dry-bulb air temperature can be used
to determine the maximum relative humidity to be allowed in the structure. This
training manual only provides a simplified or abridged version of the
psychrometric chart. A full chart also includes scales for absolute humidity or
the weight of water per unit weight of air, density, enthalpy and a correction
for varying atmospheric pressure. Psychrometric Charts that cover higher and lower
temperature ranges are also available.

Tables have also been created to determine the Relative
Humidity from the wet-bulb and dry-bulb temperatures. While the Psychrometric
Chart is the best means of determining all the properties of moist air from
only two measured values, some people prefer the simplicity of using a table to
determine relative humidity. Table 1 shows one such table
for normal temperatures and pressures, which was adapted from the Old
Farmer's Almanac (www.almanac.com/weathercenter).

As stated in the prior example,
the Dew Point temperature is the temperature below which moisture will condense
out of air. Water will condense on a surface, such as the external surface of
an air duct, a cold pipe or a can of soda, which is at or below the dew point
temperature of the air. The dew point temperature scale is located along the
same curved portion of the chart as the wet-bulb temperature scale. However,
horizontal lines indicate equal dew point temperatures, as shown in Figures 7 and 8.

Indoor air quality can be affected
both by the quality of maintenance and by the materials and procedures used in
operating and maintaining the building components including the HVAC system.

Facility staff familiar with
building systems in general and with the features of their building in
particular are an important resource in preventing and resolving indoor air
quality problems. Facility personnel can best respond to indoor air quality
concerns if they understand how their activities affect indoor air quality. It
may be necessary to change existing practices or introduce new procedures in
relation to:

Equipment operating schedules:Confirm that the
timing of occupied and unoccupied cycles is compatible with actual occupied
periods, and that the building is flushed by the ventilation systems before
occupants arrive. ASHRAE 62-1989 provides guidance on lead and lag times for
HVAC equipment.In hot, humid climates, ventilation may be needed during
long unoccupied periods to prevent mold growth.

Control of odors and
contaminants:Maintain appropriate pressure relationships between
building usage areas. Avoid recirculation of air from areas that are strong
sources of contaminants (e.g., smoking lounges, chemical storage areas, beauty
salons). Provide adequate local exhaust for activities that produce odors, dust
or contaminants, or confine those activities to locations maintained under
negative pressure (relative to adjacent areas). Make sure that paints, solvents
and other chemicals are stored and handled properly, with adequate (direct
exhaust) ventilation provided. If local filter traps and adsorbents are used,
they require regular maintenance.

Ventilation quantities:Compare outdoor air
quantities to the building design goal and local and state building codes and
make adjustments as necessary. It is also informative to see how the
ventilation rate compares to ASHRAE 62-1989, since that guideline was developed
with the goal of preventing IAQ problems.Because of recent IAQ litigation, many HVAC system
designers view ASHRAE Standard 62-89, Ventilation Standard for Acceptable
Indoor Air Quality, as a minimum ventilation standard that must be met, in
addition to local codes. If a building designer fails to conform to appropriate
ASHRAE standards, claims of negligence and strict product liability may result.
Also, building regulations in many states reference ASHRAE 62-89 for
ventilation requirements.

HVAC equipment maintenance
schedules:Inspect all equipment regularly (per recommended
maintenance schedule) to ensure that it is in good condition and is operating
as designed. Most equipment manufacturers provide recommended maintenance
schedules for their products. Components exposed to water require scrupulous
maintenance to prevent microbiological growth.

Table 2
presents strategies for responding to water damage within 24-48 hours. These
guidelines are designed to help avoid the need for remediation of mold growth
by taking quick action before growth starts. If mold growth is found on the
materials listed in Table 2, refer to Table 3
for guidance on remediation. Depending on the size of the area involved and
resources available, professional assistance may be needed to dry an area quickly
and thoroughly.

Tables 2 and 3 contain general guidelines. Their purpose is to
provide basic information for technicians to assess the extent of the damage
and then to determine whether the additional mold remediation specialists
need to be contracted for the clean-up.

May be dried in place if there is no obvious swelling and
the seams are intact. If not, remove, discard, and replace. Ventilate the
wall cavity, if possible.

Window drapes

Follow laundering or cleaning instructions recommended by
the manufacturer.

Wood surfaces

Remove moisture immediately and use dehumidifiers, gentle
heat, and fans for drying. (Use caution when applying heat to hardwood
floors.)
Treated or finished wood surfaces may be cleaned with mild detergent and
clean water and allowed to dry.
Wet paneling should be pried away from wall for drying.

(1)If mold growth has occurred or
materials have been wet for more than 48 hours, consult Table
2 guidelines. Even if materials are dried within 48 hours, mold growth may
have occurred.

These guidelines are for damage caused by clean water. If
the water source is contaminated with sewage, or chemical or biological pollutants,
then Personal Protective Equipment and containment are required by OSHA. An
experienced professional Hazardous Material Handling Expert should be
consulted. Do not use fans before determining that the water is clean or
sanitary.

(2) The subfloor under the carpet or other
flooring material must also be cleaned and dried. See the appropriate section
of Table 1 for recommended actions depending on the
composition of the subfloor.

(3) A hard surface cleaner (with biocide) is
only to be used on hard, non-porous surfaces. If metal ducts have a fiberglass
insulation inner liner, then wet sections of the liner need to be replaced.

It is impossible to eliminate all mold and mold spores
indoors; some mold spores will be found floating through the air and in dust. The
mold spores will not grow if moisture is not present. Indoor mold growth can
and should be prevented or controlled by controlling moisture indoors. If there
is mold growth in a structure, remove the mold and wet materials, including
duct board and insulation, treat the surfaces with the proper products and fix
the water problem. If the mold is cleaned-up, but the water problem is not
fixed, the mold problem will recur. Keep indoor relative humidity below 55%
(ideally between 30 and 50% relative humidity).

Table 3 presents remediation
guidelines for building materials that have or are likely to have mold growth.
The guidelines in Table 3 are designed to protect the
health of occupants and clean-up personnel during remediation. These guidelines
are based on the area and type of material affected by water damage and/or mold
growth.

If possible, remediation activities should be scheduled
during off-hours when building occupants are less likely to be affected.

Although the level of personal protection suggested in these
guidelines is based on the total surface area contaminated and the potential
for technician and/or occupant exposure, professional judgment should always
play a part in any remediation decisions. These remediation guidelines are
based on the size of the affected area to make it easier for technicians to
select appropriate techniques, not on the basis of health effects or research
showing there is a specific method appropriate at a certain number of square
feet. The guidelines have been designed to help construct a remediation plan.
The technician must use professional judgment and experience to adapt the
guidelines to particular situations. When in doubt, caution is advised.

In cases where a particularly toxic mold species has been
identified or is suspected, when extensive hidden mold is expected (such as
behind vinyl wallpaper or in the HVAC system), when the chances of the mold
becoming airborne are estimated to be high, or sensitive individuals (e.g.,
those with severe allergies or asthma) are present, a significantly more
cautious and conservative approach to remediation should be followed. Always
make sure to protect yourself and building occupants from exposure to mold or
mold spores. If anyone reports health concerns, consult a health professional
immediately. For immediate health concerns, call 911.

SMALL AREA - Total Surface Area Affected Less Than 10
square feet (ft2)

Material

Cleanup Methods(2)

Personal
Protective Equipment(1)

Containment

Books and papers

- HEPA vacuum

Minimum:
- N-95 respirator
- Gloves
- Goggles

None required

Carpet and backing

-Wet vacuum
- HEPA vacuum

Minimum:
- N-95 respirator
- Gloves
- Goggles

None required

Concrete or cinderblock

- Wet vacuum
- HEPA vacuum

Minimum:
- N-95 respirator
- Gloves
- Goggles

None required

Hard surface, porous flooring
(linoleum, ceramic tile, vinyl)

- Wet vacuum
- Damp wipe
- HEPA vacuum

Minimum:
- N-95 respirator
- Gloves
- Goggles

None required

Non-porous, hard surfaces
(plastics, metals)

- Wet vacuum
- Damp wipe
- HEPA vacuum

Minimum:
- N-95 respirator
- Gloves
- Goggles

None required

Upholstered furniture and drapes

- Wet vacuum
- HEPA vacuum

Minimum:
- N-95 respirator
- Gloves
- Goggles

None required

Wallboard
(drywall and gypsum board)

- HEPA vacuum

Minimum:
- N-95 respirator
- Gloves
- Goggles

None required

Wood surfaces

- Wet vacuum
- Damp wipe
- HEPA vacuum

Minimum:
- N-95 respirator
- Gloves
- Goggles

None required

MEDIUM AREA - Total Surface Area Affected Between 10
and 100 ft2

Material

Cleanup Methods(2)

Personal
Protective Equipment(1)

Containment

Books and papers

- HEPA vacuum

Limited or Full

Use professional judgment, consider potential for remediator exposure and
size of contaminated area.

Limited

Use professional
judgment, consider potential for remediator/occupant exposure and size of
contaminated area.

Carpet and backing

- Wet vacuum
- HEPA vacuum
- Discard

Limited or Full

Use professional judgment, consider potential for remediator exposure and
size of contaminated area.

Limited

Use professional
judgment, consider potential for remediator/occupant exposure and size of
contaminated area.

Concrete or cinder block

- Wet vacuum
- HEPA vacuum

Limited or Full

Use professional judgment, consider potential for remediator exposure and
size of contaminated area.

Limited

Use professional
judgment, consider potential for remediator/occupant exposure and size of
contaminated area.

Hard surface, porous flooring (linoleum, ceramic tile,
vinyl)

- Wet vacuum
- Damp wipe
- HEPA vacuum

Limited or Full

Use professional judgment, consider potential for remediator exposure and
size of contaminated area.

Limited or Full

Use professional judgment, consider potential for remediator exposure and
size of contaminated area.

Non-porous, hard surfaces (plastics, metals)

- Wet vacuum
- Damp wipe
- HEPA vacuum

Limited or Full

Use professional judgment, consider potential for remediator exposure and
size of contaminated area.

Limited

Use professional
judgment, consider potential for remediator/occupant exposure and size of
contaminated area.

Upholstered furniture and drapes

- Wet vacuum
- HEPA vacuum
- Discard

Limited or Full

Use professional judgment, consider potential for remediator exposure and
size of contaminated area.

Limited

Use professional
judgment, consider potential for remediator/occupant exposure and size of
contaminated area.

Wallboard
(drywall and gypsum board)

- HEPA vacuum
- Discard

Limited or Full

Use professional judgment, consider potential for remediator exposure and
size of contaminated area.

Limited or Full

Use professional judgment, consider potential for remediator exposure and
size of contaminated area.

Wood surfaces

- Wet vacuum
- Damp wipe
- HEPA vacuum

Limited or Full

Use professional
judgment, consider potential for remediator exposure and size of contaminated
area.

Limited

Use professional
judgment, consider potential for remediator/occupant exposure and size of
contaminated area.

LARGE - Total Surface Area Affected Greater Than 100 ft2
or Potential for Increased Occupant or Remediator Exposure
During Remediation Estimated to be Significant

Material

Cleanup Methods(2)

Personal
Protective Equipment(1)

Containment

Books and papers

- HEPA vacuum

Full

Use professional judgment, consider potential for remediator exposure and
size of contaminated area.

Full

Use professional judgment, consider potential for remediator/occupant
exposure and size of contaminated area.

Carpet and backing

- Wet vacuum
- HEPA vacuum
- Discard

Full

Use professional judgment, consider potential for remediator exposure and
size of contaminated area.

Full

Use professional judgment, consider potential for remediator/occupant
exposure and size of contaminated area.

Concrete or cinder block

- Wet vacuum
- HEPA vacuum

Full

Use professional judgment, consider potential for remediator exposure and
size of contaminated area.

Full

Use professional judgment, consider potential for remediator/occupant
exposure and size of contaminated area.

Hard surface, porous flooring (linoleum, ceramic tile,
vinyl)

- Wet vacuum
- Damp wipe
- HEPA vacuum
- Discard

Full

Use professional judgment, consider potential for remediator exposure and
size of contaminated area.

Full

Use professional judgment, consider potential for remediator/occupant
exposure and size of contaminated area.

Non-porous, hard surfaces (plastics, metals)

- Wet vacuum
- Damp wipe
- HEPA vacuum

Full

Use professional judgment, consider potential for remediator exposure and
size of contaminated area.

Full

Use professional judgment, consider potential for remediator/occupant
exposure and size of contaminated area.

Upholstered furniture and drapes

- Wet vacuum
- HEPA vacuum
- Discard

Full

Use professional judgment, consider potential for remediator exposure and
size of contaminated area.

Full

Use professional judgment, consider potential for remediator/occupant
exposure and size of contaminated area.

Wallboard (drywall and gypsum board)

- HEPA vacuum
- Discard

Full

Use professional judgment, consider potential for remediator exposure and
size of contaminated area.

Full

Use professional judgment, consider potential for remediator/occupant
exposure and size of contaminated area.

Wood surfaces

- Wet vacuum
- Damp wipe
- HEPA vacuum
- Discard

Full

Use professional judgment, consider potential for remediator exposure and
size of contaminated area.

Full

Use professional judgment, consider potential for remediator/occupant
exposure and size of contaminated area.

(1) Use professional judgment to determine
prudent levels of Personal Protective Equipment and containment for each
situation, particularly as the remediation site size increases and the
potential for exposure and health effects rises. Assess the need for increased
Personal Protection Equipment, if, during the remediation, more extensive
contamination is encountered than was expected. Consult Table 2
if materials have been wet for less than 48 hours, and mold growth is not
apparent.

These guidelines are for damage caused by clean water. If
you know or suspect that the water source is contaminated with sewage, or
chemical or biological pollutants, then the Occupational Safety and Health
Administration (OSHA) requires PPE and containment. A HAZMAT certified
professional should be contracted.

(2) Select method most appropriate to
situation. Since molds gradually destroy the things they grow on, if mold
growth is not addressed promptly, some items may be damaged such that cleaning
will not restore their original appearance. Please note that these are
guidelines; other cleaning methods may be preferred by some professionals.

Method 1: Wet vacuum. For porous duct materials, some
mold spores/fragments will remain in the material. Replacement of this porous
duct material is always recommended.

Method 2: Clean nonporous surfaces with a hard surface
cleaner that contains a biocide. Whether dead or alive, mold is allergenic, and
some molds may be toxic. Mold can generally be killed and removed from
nonporous (hard) surfaces by wiping with a hard surface cleaner that contains a
biocide. Instructions for using any hard surface cleaner should always be read
and followed. Porous materials that are wet and have mold growing on them will
have to be discarded because the molds will infiltrate porous substances and
grow on or fill in empty spaces or crevices, making it impossible to remove
these molds completely.

Method 3: High-efficiency particulate air (HEPA) vacuum after
the material has been thoroughly dried. Dispose of the contents of the HEPA
vacuum in sealed plastic bags.

HEPA (High-Efficiency Particulate Air) vacuums are
recommended for final cleanup of remediation areas after materials have been
thoroughly dried and contaminated materials removed. HEPA vacuums are also
recommended for clean-up of dust that may have settled on surfaces outside the
remediation area. Care must be taken to assure that the filter is properly
seated in the vacuum so that all the air must pass through the filter. When
changing the vacuum filter, wear PPE to prevent exposure to the mold that has
been captured. The filter and contents of the HEPA vacuum must be disposed of
in well-sealed plastic bags.

Method 4: Discard water-damaged materials and
seal in plastic bags while inside of containment, if present. HEPA vacuum area
after it is dried.

Building materials and furnishings that are contaminated
with mold growth and are not salvageable should be double-bagged using 6-mil
polyethylene sheeting. These materials can usually be discarded as ordinary
construction waste. It is important to package mold contaminated materials in
sealed bags before removal from the containment area to minimize the dispersion
of mold spores throughout the building. Large items that have heavy mold growth
should be covered with polyethylene sheeting and sealed with duct tape before
they are removed from the containment area.

Limited: Use polyethylene sheeting ceiling to
floor around affected area with a slit entry and covering flap; maintain area
under negative pressure with HEPA filtered fan unit. Block supply and return
air vents within containment area.

Full: Use two layers of fire-retardant
polyethylene sheeting with one airlock chamber. Maintain area under negative
pressure with HEPA filtered fan exhausted outside of building. Block supply and
return air vents within containment area.

Table developed from literature and remediation documents
including Bioaerosols: Assessment and Control (American
Conference of Governmental Industrial Hygienists, 1999) and IICRC S500,
Standard and Reference Guide for Professional Water Damage Restoration (Institute
of Inspection, Cleaning and Restoration, 1999).

Mainstream manufactures a Surface-sample Mold Test Kit,
known as the QwikTreatTMMoldTestTM Kit,
for use by trained HVAC/R technicians when identification of a mold is desired.
For situations where litigation is involved, the source(s) of the mold
contamination is unclear, or health concerns are a problem, consider sampling
as part of a site evaluation. Surface sampling may also be useful in order to
determine if an area has been adequately cleaned. Sampling should be done only
after developing a sampling plan that includes a confirmable theory regarding
suspected mold sources and routes of exposure. Attempt to determine what is
occurring and how to prove or disprove it before sampling is conducted!

The results of sampling may have limited use or application.
Sampling may help locate the source of mold contamination, identify some of the
mold species present, and differentiate between mold and soot or dirt. Pre- and
post-remediation sampling may also be useful in determining whether remediation
efforts have been effective. Since no EPA or other federal threshold limits
have been set for mold or mold spores, air sampling cannot be used to check a
building's compliance with federal mold standards. Sample analyses should
follow analytical methods recommended by the American Industrial Hygiene
Association (AIHA) or the American Conference of Governmental Industrial
Hygienists (ACGIH). Types of samples include air samples, surface samples, bulk
samples (chunks of duct board, carpet, insulation, wall board, etc.), and water
samples from condensate drain pans, humidifiers or cooling towers. Surface
sample testing is an ideal method of identifying molds that are actually
growing in the structure.

Keep in mind that testing for mold provides temporary information,
much like a snapshot. When properly performed, surface sampling will reveal
what was growing on a particular surface at the moment when the sample was
taken.

If the duct board is wet or moldy or the
insulation on sheet metal air ducts gets wet or moldy, they cannot be
effectively cleaned and they must be removed and replaced.

▶If
the conditions causing the mold growth in the first place are not corrected,
mold growth will recur. Treating with biocides, such as those contained in a hard
surface cleaner, will kill the mold growth, but the mold will eventually return
if the moisture problem is not resolved. It is critical to solve the
moisture problem.

▶Duct
cleaning has never been shown to actually prevent health problems. Furthermore,
research studies do not conclusively demonstrate that particle levels in
buildings increase because of dirty air ducts or decrease after cleaning. This
is because much of the dirt that may accumulate inside air ducts adheres to
duct surfaces and does not necessarily enter the living space. It is important
to keep in mind that dirty air ducts are only one of many possible sources of
particles that are present in buildings. Pollutants enter a structure both from
outdoors and indoor activities, such as cooking, cleaning, smoking, or ordinary
movement within a building. There is no evidence that a light amount of dust or
other particulate matter in air ducts poses any risk to health. Conversely, any
mold observed must be removed. For hard surfaces, that means cleaning with a hard
surface cleaner while for porous surfaces the moldy porous material must be
removed--mold on porous surfaces cannot be effectively treated, it must be
removed.

▶The
EPA does not recommend that air ducts be cleaned because of the
continuing uncertainty about the benefits of duct cleaning. Any service
provider or advertiser who asserts that the EPA recommends routine duct
cleaning or makes claims about the health benefits should be reported to the
EPA.

▶The
EPA does recommend fuel burning furnaces, stoves or fireplaces be inspected for
proper functioning and serviced before each heating season to protect against
carbon monoxide poisoning. Research also suggests that cleaning
dirty cooling coils, fans and heat exchangers can improve the efficiency and
capacity of heating and cooling systems and remove the food sources on which
molds and bacteria rely.

▶Do
not paint or caulk moldy surfaces; clean and dry surfaces before painting.
Paint applied over moldy surfaces is likely to peel.

▶The
purpose of mold remediation is to remove the mold to prevent human exposure and
damage to building materials and furnishings.

▶Be
sure to clean up the mold contamination, not just kill the mold. Dead
mold is still allergenic, and some dead molds are potentially toxic.

▶The
use of chlorine bleach is not recommended to kill mold. For hard, non-porous
surfaces, use a hard surface cleaner, and for porous fibrous insulation and
fiberboard the material must be replaced. Chemical
biocides can only be used on hard, non-porous surfaces. Never use any of these
compounds when immune-compromised individuals are present. Remember, biocides
are toxic to humans, as well as to mold. Appropriate PPE should be used. Read
and follow label precautions.

▶Never
mix chlorine bleach solution with any other cleaning solutions or detergents
that contain ammonia; toxic fumes could be produced.

▶It
is not possible or desirable to sterilize an area; a background level of mold spores
will always remain in the air (roughly equivalent to the level in outside air).
These spores will not grow if the moisture problem in the building has been
resolved.

▶When
using fans to dry or ventilate, be careful not to distribute mold spores throughout
an unaffected area.

▶Fungicides
are commonly applied to outdoor plants, soil, and grains as a dust or spray – examples
include hexachlorobenzene, organomercurials, pentachlorophenol, phthalimides,
and dithiocarbamates.Do not use fungicides developed for use for mold
remediation or for any other indoor situation. Death could occur without
warning!

In this manual, duct cleaning does
not refer to the cleaning of the registers grilles and diffusers, furnace heat
exchangers and A/C cooling coils, condensate drain pans (drip pans), humidifiers,
fan motors and housings, or the air handling unit housing. Rather duct cleaning
refers to the cleaning of the actual porous or non-porous duct itself.

If not properly installed,
maintained and operated, portions of the heating, air conditioning or
ventilating system can become contaminated with particles of dust, pollen or
other debris. If moisture is present, the potential for microbiological growth
is increased and spores from such growth may be released into the building's
living space. As discussed previously, these contaminants can cause allergic
reactions or other symptoms in certain people who are exposed to them.

Chemical biocides
designed to kill microbiological contaminants should not be applied to the
inside of porous ductwork because the EPA has not yet determined the safety of
such an approach. No product is EPA certified for this use, in part, because
the EPA has not resolved these issues. Since biocides kill living organisms,
they could cause serious health problems if inhaled by the service technician
or the building occupants. These
health concerns are especially serious if pregnant woman or small children are
exposed. All biocide products should
never be used in a fashion that would allow the service technician or the
occupants any possibility of inhalation.

Chemical treatments
(sealants or other encapsulants) are available that can encapsulate or cover
the inside surfaces of the air ducts and equipment housings to prevent the
release of dirt particles or fibers from ducts, however, these products
should only be applied after the system has been properly cleaned of all
visible dust or debris and any wet or moldy sections removed and replaced.
Cleaning products that contain biocides (essentially poisons) must be
registered with the EPA and display the EPA-Registration number on the
packaging. Products that will kill mold while also encapsulating or sealing
porous surfaces that contain mold preventing biocides are not registered with
the EPA, since the biocide is encapsulated into the cured surface. Follow all
label directions.

Never make
general claims about the health benefits of duct cleaning--such claims are
unsubstantiated. If improperly done, duct cleaning can dislodge dirt and mold
causing health problems. Do not recommend duct cleaning as aroutinepart of heating and
cooling system maintenance. Never claim to be certified by the EPA in duct
cleaning.The EPA neither establishes duct-cleaning standards nor
certifies, endorses, or approves duct cleaning companies. Check with the state department of professional
regulation; many states including Arizona, Arkansas, California, Florida,
Georgia, Michigan and Texas require air duct cleaners to hold special licenses.
Other states may require them as well.

The information about the
potential benefits and possible problems of air duct cleaning is limited, and
the EPA is still investigating the issues. In general, conditions in every
structure are different; it is impossible to generalize about whether or not
air duct cleaning would be beneficial at a specific location. Use common sense
and training to assess each individual situation. Generally speaking, if no one
in the structure is reporting any unexplained allergies, unexplained symptoms
or unexplained illnesses and if, after a visual inspection of the systems and
ductwork, there is no clear indication that the system or the air ducts are
contaminated with large deposits of dust or any mold (no musty odor or visible
mold growth), it is probably not necessary to clean the air ducts. Therefore,while
routine duct cleaning is not recommended, the evaporator coil, humidifier, and
condensate drain pan should always be cleaned and the condensate drain line or
condensate pump checked for proper operation. After cleaning the evaporator coil and humidifier water
box, a hard surface cleaner should be used to kill and remove mold and other
growths, Pan tablets should be added to prevent the future accumulation of any
type of scum. Use a hard surface cleaner on any hard surfaces where mold may be
suspected.

It is normal for the
return registers to become dusty as dust-laden air is pulled through the grate.
This does not indicate that the air ducts are contaminated with heavy deposits
of dust or debris; the registers and the duct region surrounding the registers
can be easily removed and cleaned. This is always a recommended practice, as is
cleaning the evaporator coil, humidifier, and condensate pan.

If building occupants are experiencing unusual or unexplained
symptoms or illnesses they should discuss the situation with their doctor,
including the question of whether these symptoms could be the result of
indoor air pollution.

Some equipment owners may want their air ducts cleaned
simply because it seems logical that air ducts will become dirty over time and
should occasionally be cleaned. While the debate about the value of periodic
duct cleaning continues, no evidence suggests that such cleaning would be
detrimental, provided that it is done properly. However, if
a service technician fails to follow proper duct cleaning procedures, duct cleaning
can cause indoor air problems. For example, an inadequate vacuum
collection system can release more dust, dirt and other contaminants. A
careless or inadequately trained service provider can also damage the air ducts
or heating and cooling system. Table 4 presents a
duct-cleaning checklist.

Mainstream recommends the following duct cleaning and
treatment procedure:

1)Inspect the duct
work for any air leaks. Conditioned air that leaks into unconditioned spaces,
while wasting money, can also lead to condensation and moisture problems on the
ductwork.

2)Inspect the duct
work for improper or missing insulation in un-conditioned spaces. Cool
exterior duct surfaces in unconditioned spaces, while wasting money, can also
lead to condensation and moisture problems on the ductwork.

3)Inspect the duct
work and mastic seals for any signs of exterior mold or condensation. This can
be caused by insufficient thermal insulation of the ductwork or air leaks from
the ducts. If mold is found, it must be removed completely, along with any
other wet insulation or fiberboard. Any non-porous surfaces including metal
ducts should be cleaned and treated with a hard surface cleaner. Make sure any
replacement duct work areas are fully insulated. For fiber-board ducts, the
moisture could have soaked through to the inside surface, causing mold
formation on the inside of the duct. The entire wet or moldy section of duct
board must be replaced. In summary, replace all wet or moldy porous materials. Alternatively,
clean any non-porous hard surfaces with a hard surface cleaner.

4)Inspect the
interior of the ductwork at all registers and returns. Wearing protective
equipment and with the air handler off, vacuum out any loose debris and look
for signs of mold. Use a high-suction vacuum with a HEPA filter to remove any
loose debris. If mold is found in any porous material, the material must be cut
out and replaced.

Whenever mold
is discovered, the moisture source must be identified and repaired, and the
wet or moldy area replaced and treated.

5)Inspect the air
handler for the presence of mold or excessive contamination. Check that the
blower wheel is free spinning to avoid reduced airflow. A hard surface cleaner
can be used to kill and remove mold from any of these hard surfaces. Use a pan tablet
in the condensate pan, humidifier or condensate line tablet dispenser to
prevent the build-up of scum, which could clog the condensate line and result
in local flooding and future mold growth.

The bottom line is: no one knows. There are examples of
ducts that have become badly contaminated with a variety of materials that may
pose risks to one's health. In these cases, the duct system can serve as a
means to distribute these contaminants throughout a building. Obviously, in
these cases, duct cleaning makes sense. However, a light amount of dust in the
air ducts is normal. It is also normal for the air return register to
become dusty as dust-laden air is pulled through it. The register should be
cleaned periodically. However, duct cleaning is not considered to be a
necessary part of yearly maintenance of a properly maintained heating or
cooling system. Research continues in an effort to evaluate the potential
benefits of air duct cleaning.

However, a properly maintained heating or cooling system
maintenance routine must include regular cleaning of drain pans, use of Pan
Treatment Tablets during the cooling system and at least annual cleaning of the
furnace heat exchanger and A/C evaporator coils, regular (at least monthly)
filter changes using PuraClean® and annual inspections
of both the furnace and cooling system prior to the beginning of a new heating
or cooling season. The furnace inspection should include a heat exchanger leak
test.

Should chemical biocides
or ozone be sprayed into air ducts?

Some chemical companies try to sell products for air duct
cleaning that claim a chemical biocide should be applied to the entire inside
surface of the air ducts to kill bacteria (germs), and fungi (mold) and prevent
future biological growth. Typically, anything that kills living organisms like
bacteria and fungi is also not healthy for humans, so the widespread spraying
of such compounds into the air is not a good idea, unless the building is
unoccupied for a substantial period of time after the spraying (and even then
these killing compounds could be distributed on eating surfaces and food
supplies). Exposure in this case is even more of a problem for pregnant or
nursing women and small children. Of course, the technician performing the
spraying must wear protective breathing apparatus. It is exactly because of the
unknown variables that the EPA has not approved any substance for this type of
application. There are always ample mold spores and bacteria in the air,
therefore, a one-time killing of the bacteria and mold will not prevent a
recurring problem because new bacteria and mold spores will simply start
re-growing in the water and dirt remaining in the duct work. The removal of the
source of water and dirt (the food supply) is the only real solution to
preventing recurring problems.

Both the EPA and Mainstream recommend the removal of any wet
or moldy duct board or fiberglass insulation.

Some manufacturers propose to introduce ozone to kill
biological contaminants. Ozone is a highly reactive gas, meaning it is a highly
corrosive gas that is regulated in the outside air as a lung irritant. It
is not recommended to purposely introduce ozone into the air due to the
corrosive and toxic properties of this gas. There are many components
of the air handling system that would be adversely affected by a corrosive gas.
There is no logical reason for the widespread introduction of either chemical
biocides or ozone into the duct work. The following are among the possible
problems with biocide and ozone application in air ducts:

▶Little
research has been conducted to demonstrate the effectiveness of most biocides
and ozone when used inside ducts. Simply spraying or otherwise introducing
these materials into the operating duct system may cause much of the material
to be transported through the system and released into other living areas of
the structure.

▶Some
people may react negatively to the biocide or ozone, causing adverse health
reactions.

EPA regulates chemical biocides under federal pesticide
laws. EPA must register a product for a specific use before it can be legally
used for that purpose. The specific use(s) must appear on the pesticide (e.g.,
biocide) label, along with other important information. It is a violation of
federal law to use a pesticide product in any manner inconsistent with the
label directions.

EPA currently registers a small number of products
specifically for use on the inside of bare sheet metal air ducts. A
number of products are registered for use as sanitizers on hard surfaces,
which includes the interior of bare sheet metal ducts. While many such products
may be used legally inside of unlined non porous ducts if all label directions
are followed, some of the directions on the label may be inappropriate for
use in ducts and therefore those products should not be used inside air ducts. For
example, if the directions indicate, "rinse with water", the added
moisture could stimulate mold growth. There are no products currently
registered by the EPA for cleaning fibrous (porous) air ducts, porous flexible
ducts or metal ducts with internal fiberglass insulation, even though some
manufacturers may claim otherwise. This is partly because the EPA currently has
no approved method to test the safety and effectiveness of such
products.

Before using any product claimed to be EPA-registered, check
with the EPA. Also, if the product is registered, it is only to be used
according to the instructions printed on the can because it has been tested and
deemed safe only for that method of use. Some companies have offered
flyers or pamphlets that offer instructions that are substantially different
from the labeled instructions. However, it is a violation of
federal law to use an EPA-registered product in any manner inconsistent
with the label directions. Failure to follow label instructions can introduce
potential liability issues for the IAQ technician.

Manufacturers of products marketed to coat and encapsulate
duct surfaces claim that they prevent dust and dirt particles inside air ducts
from being released into the air. Actually, any duct surface should be
thoroughly cleaned before any sealant is applied. The use of sealants to coat
the duct surfaces is appropriate for the repair of damaged fiberglass
insulation or when combating fire damage within ducts. Sealants should never be
used on wet or dirty ducts either to cover actively growing mold, or to cover
debris in the ducts. Sealants should only be applied after replacement of wet
or moldy sections and system cleaning. A duct sealant, like many paints, is combined
with a biocide to help prevent recurrence of mold on the surfaces. These
duct sealants should not be indiscriminately sprayed into entire duct systems,
since the vapors are harmful to breathe. Follow all label directions.

▶Open
access ports or doors to allow the entire system to be cleaned and
inspected.

▶Inspect
the system before cleaning to be sure that there are no asbestos-containing
materials (e.g., insulation, register boots, etc.) in the heating and cooling
system. Asbestos-containing materials require specialized procedures and should
not be disturbed or removed except by specially trained and equipped Asbestos
Removal Contractors.

▶Use
vacuum equipment that exhausts particles outside of the building or use only
high-efficiency particle air (HEPA) vacuuming equipment if the vacuum exhausts
inside the building.

▶Protect
carpet and furnishings during cleaning.

▶Use
well-controlled brushing of duct surfaces in conjunction with contact vacuum
cleaning to dislodge dust and other particles.

▶Use
only soft-bristled brushes for fiberglass duct board and sheet metal ducts
internally lined with fiberglass. (Although flex duct can also be cleaned using
soft-bristled brushes, it can be more economical to simply replace accessible
flex duct.)

▶Take
care to protect the duct work, including sealing and re-insulating any access
holes made or used so they are airtight.

Communication with building occupants is essential for
successful IAQ treatments and mold remediation. Some occupants will naturally
be concerned about indoor air quality and mold growth in their building and the
potential health impacts. The perceptions of health risks may increase if
occupants feel that information is being withheld from them. The status of the
building investigation and treatment should be openly communicated, including
information on any known or suspected health risks.

Special communication strategies may be desirable when
treating a mold problem in a school. Teachers, parents and other locally
affected groups should be notified of significant issues immediately after they
are identified. Consider holding a special meeting to provide parents with an
opportunity to learn about the problem and ask questions of school authorities.
It is advisable to ensure that the school is vacated during remediation.

For more information on investigating IAQ and remediation in
schools, refer to the U.S. EPA's IAQ Tools for Schools kit and
the asthma companion piece for the IAQ Tools for Schools kit,
titled Managing Asthma in the School Environment.

Small remediation efforts will usually not require a formal
communication process, but be sure to take individual concerns seriously and
use common sense when deciding whether formal communications are required.
Individuals managing medium or large remediation efforts should make sure they
understand and address the concerns of building occupants and communicate
clearly what has to be done, as well as any possible health concerns.

Communication approaches include regular memos and/or
meetings with occupants (with time allotted for questions and answers),
depending on the scope of the remediation and the level of occupant interest.
Inform the occupants about the size of the project, planned activities, and
remediation timetable. Send or post regular updates on the remediation
progress, and send or post a final memo when the project is completed or hold a
final meeting. Try and resolve issues and occupant concerns as they occur. When
building-wide communications are frequent and open, those managing the remediation
can direct more time toward resolving the problem.

If possible, remediation activities should be scheduled
during off-hours when building occupants are less likely to be affected.
Communication is important if occupants are relocated during remediation. The
decision to relocate occupants should take into consideration the size of the
area affected, the extent and types of health effects exhibited by the
occupants, and the potential health risks associated with debris and activities
during the remediation project. When considering the issue of relocation, be
sure to inquire about, accommodate, and plan for individuals with asthma,
allergies, compromised immune systems, and other health-related concerns. Ease
the relocation process and give occupants an opportunity to participate in the
resolution of the problem by clearly explaining the work process and work
schedules. Notify individuals of relocation efforts in advance, if possible.

There will be some
people, especially children, that will exhibit more severe adverse reactions,including death, lung tissue damage, and memory loss when exposed to
molds. The severity of the reaction depends on the chemical sensitivity,
genetic disposition, predisposing health history (such as allergies, asthma,
smoking, etc.). For some, the exposure to the toxic mold spores may just be a
"health risk" and to others, it may be a viable "health
hazard" (potential life-threatening and loss of "quality of
life"). Given the magnitude of this issue, there is a potentialliability concern.

IAQ
Technicians should not make claims or representations that "all the mold
or mold spores have been removed", or that "the area is completely treated
and safe." Mold spores are always in the air. The best that can be done is
the removal of the source of moisture and the removal of any existing mold. Advise
occupants to check with their doctor concerning any existing or future risks
associated with inhabiting the structure.

It is wise to instruct the
building occupants that mold and air quality testing can be performed, and they
should seek the advice of their physician concerning this and other tests. Inform
the building occupants that they should also check with their local county or
city health department for additional health-related guidance.

Contact local county or city
health departments in the service area to determine if there are any additional
procedures (and licenses) that they specifically recommend.

It is also wise to
obtain properliability insurancebefore performing any IAQ-related services. There are
already several major lawsuits concerning toxic mold exposure in residential
and commercial buildings throughout the United States. Do not take this matter
lightly;toxic mold can be deadly.
Be careful to protect yourself and the building occupants from exposure and
serious medical consequences.

Make it clear to the building
owner and occupants that if the source of moisture causing the mold growth is
not removed,nothingwill stop the recurrence of the problem. Some technicians have included this information as a part
of their work order estimate. It is a good idea to have the building owner sign
to acknowledge a statement such as this.

Section
IV:

If the remediation job disturbs mold and the mold becomes
airborne, then the risk of respiratory exposure increases. Actions
that are likely to stir up mold include removal of moldy duct insulation and
fiberboard, removal of building insulation, breakup of moldy porous materials
such as wallboard; invasive procedures used to examine or remediate mold growth
in a duct work and wall cavities; actively stripping or peeling wallpaper to
remove it; and using fans to dry items.

Spraying of biocides will also introduce potentially toxic
substances into the air, and possibly into the lungs of service technicians and
occupants. Biocides should never be sprayed into operating systems, since this
would make these toxic chemicals airborne and significantly more dangerous.

The primary function of Personal
Protective Equipment (PPE) is to avoid inhaling mold and mold spores
and to avoid mold contact with the skin or eyes. The following sections discuss
the different types of PPE that can be used during remediation activities.

All
individuals using certain PPE equipment, such as half-face or full-face
respirators, must be trained, must have medical clearance, and must be
fit-tested by a trained professional. In addition,the use of respirators must
follow a complete respiratory protection program as specified by the
Occupational Safety and Health Administration.

Always use gloves and eye protection when cleaning up mold
or applying mold treatment and duct sealant products!

Gloves are required to protect the skin from
contact with mold allergens (and in some cases mold toxins) and from
potentially irritating disinfection and sealing compounds. Long gloves that
extend to the middle of the forearm are recommended. The glove material should
be selected based on the type of materials being handled.

To protect the eyes, use properly fitted goggles or a
full-face respirator with HEPA filter. Goggles must be designed
to prevent the entry of dust and small particles. Safety glasses or goggles
with open vent holes are not acceptable.

When cleaning up a small area affected by mold,
use an N-95 respirator. This device covers the nose and mouth, will filter out
95% of the particulates in the air, and is available in most hardware stores.

Limited PPE includes use of a half-face or full-face
air-purifying respirator (APR) equipped with a HEPA filter cartridge. These
respirators contain both inhalation and exhalation valves that filter the air
and ensure that it is free of mold particles. Note that half-face APRs do not
provide eye protection. In addition, the HEPA filters do not remove
vapors or gases (no filter removes vapors or gases). Always use
respirators approved by the National Institute for Occupational Safety and
Health.

In situations where high levels of airborne dust
or mold spores are likely or when long-term exposures are expected (cleanup of
large areas), a full-face, Powered Air Purifying Respirator (PAPR) is
recommended. Full-face PAPRs use a blower to force air through
a HEPA filter. The HEPA-filtered air is supplied to a mask that covers the
entire face or a hood that covers the entire head. The positive pressure within
the hood prevents unfiltered air from entering through penetrations or gaps.
Individuals have to be trained to use the respirators before they begin
remediation. The use of these respirators must be in compliance with OSHA
regulations.

Disposable clothing is recommended during a medium or large
remediation project to prevent the transfer and spread of mold to clothing and
to eliminate skin contact with mold.

Limited:Disposable paper
overalls can be used.

Full:Mold-impervious
disposable head and foot coverings, and a body suit made of a breathable
material, such as TYVEK®, should be used. All gaps, such as those around ankles and
wrists, should be sealed (many remediators use duct tape to seal clothing).

The purpose of containment during
remediation activities is to limit release of mold into the air and
surroundings in order to minimize the exposure of remediators and building
occupants to mold. Mold and moldy debris should not be allowed to spread to
areas in the building beyond the contaminated site.

The two types of containment,
recommended in Table 2,
are limited and full. The larger the area of moldy material, the greater the
possibility of human exposure and the greater the need for containment. In
general, the size of the area helps determine the level of containment.
However, a heavy growth of mold in a relatively small area could release more
spores than a lighter growth of mold in a relatively large area. Choice of
containment should be based on professional judgment. The primary object of
containment should be to prevent occupant and remediator exposure to mold.

A remediator
may decide that a small area that is extensively contaminated and has the
potential to distribute mold to occupied areas during cleanup should have
full containment, whereas a large wall surface that is lightly contaminated
and easily cleaned would require only limited containment.

Limited containment is generally recommended for
areas involving between 10 and 100 square feet of mold contamination. The
enclosure around the moldy area should consist of a single layer of minimum
6-mil, fire-retardant polyethylene sheeting. The containment should have a slit
entry and covering flap on the outside of the containment area. For small
areas, the polyethylene sheeting can be affixed to floors and ceilings with
duct tape. For larger areas, a steel or wooden stud frame can be erected and
polyethylene sheeting attached to it.

All supply and air vents, doors, chases, and risers within
the containment area must be sealed with polyethylene sheeting to minimize the
migration of contaminants to other parts of the building. Heavy
mold growth on ceiling tiles may impact HVAC systems if the space above the
ceiling is used as a return air plenum. In this case, containment should be
installed from the floor to the ceiling deck, and the filters in the
air-handling units serving the affected area may have to be replaced once
remediation is finished.

The containment area must be maintained under negative
pressure relative to surrounding areas. This will ensure that contaminated air
does not flow into adjacent areas. This can be done with a HEPA-filtered fan
unit exhausted outside of the building. For small, easily contained areas, an
exhaust fan ducted to the outdoors can also be used. The hard surfaces of all
objects removed from the containment area should be cleaned with a hard surface
cleaner prior to removal. The remediation guidelines outlined in Table 2 can be implemented when the containment is
completely sealed and is under negative pressure relative to the surrounding
area.

Full containment is recommended for the cleanup
of mold contaminated surface areas greater than 100 square feet, or in any
situation in which it appears likely that the occupant space would be further
contaminated without full containment.

Double layers of minimum 6-mil fire-retardant polyethylene
sheeting should be used to create a barrier between the moldy area and other
parts of the building. A decontamination chamber or airlock should be
constructed for entry into and exit from the remediation area. The entryways to
the airlock from the outside and from the airlock to the main containment area
should consist of a slit entry with covering flaps on the outside surface of
each slit entry.

The decontamination chamber or airlock should be large
enough to hold a waste container and allow a person to put on and remove PPE.
While in this chamber, all contaminated PPE, except respirators, should be
placed in a sealed bag. Respirators should be worn until remediators are
outside the decontamination chamber. PPE must be worn throughout the final
stages of HEPA vacuuming and hard surface cleaner damp-wiping of the contained
area. PPE must also be worn during HEPA vacuum filter changes or cleanup of the
HEPA vacuum.

▶Use
exhaust fans (to the outdoors) and ensure that adequate makeup air is provided.

▶If
the containment is working, the polyethylene sheeting should billow inwards on
all surfaces. If it flutters or billows outward, containment has been lost.
Find and correct the problem before continuing remediation activities.